-LIBRARY 
 
 OF THE 
 UNIVERSITY 
 Of ILLI NOIS 
 
 ?R2o 
 
 o 
 
 in 
 
 CO 
 CVJ 
 
 NAFURAL 
 HISTORY 
 
Digitized by the Internet Archive 
 
 in 2011 with funding from 
 
 University of Illinois Urbana-Champaign 
 
 http://www.archive.org/details/onmorphologyofduOOpark 
 
/<?2. 
 
 <#_ 
 
 
 ROYAL IRISH ACADEMY. 
 
 "CUNNINGHAM MEMOIRS." 
 
 No. VI. 
 
 ON THE MORPHOLOGY 
 
 OF 
 
 THE DUCK AND THE AUK TRIBES. 
 
 BY 
 
 W. KITCHEN PARKER, F.R.S. 
 
 (Mitb liue flute. 
 

 Professor William Kitchen Parker died suddenly of syncope of the heart 
 on the 3rd of July, 1890, at Cardiff, while this Memoir was passing through 
 
 the press. 
 
 Should any inaccuracies appear in the text, or in the lettering of the 
 Plates, they are to be accounted for by the fact that my Father only 
 received first proofs up to p. 41 before his death. At Dr. E. Perceval 
 Wright's (Secretary of the Royal Irish Academy) request, I undertook the 
 correcting of the remaining proofs ; but, as I had not the opportunity of 
 going through the Paper with my Father first, and as the proofs, both of 
 the letterpress and of Plates V.-IX., had to be corrected as they came, 
 it was not easy for me to revise the whole Paper as satisfactorily as I 
 
 could have wished. 
 
 W. N. PARKER. 
 
 Cardiff, November 14th, 1890. 
 
"CUNNINGHAM MEMOIRS." 
 
 No. VI. 
 
 On the Morphology of the Duck Tribe (*inatitl*r) ami the Auk Tribe (■Mcidue). 
 By W. Kitchen Parker, F.R.S. (Plates I. -IX.) 
 
 [Read, February 10, 1890.] 
 
 Introductory Remarks. 
 
 The materials fur the present Paper have partly been in hand for many 
 years, whilst the rest have been obtained during the last year or two. The 
 Shoulder-girdle and Sternum of the Guillemot ( Uria troile) were described in 
 two stages in my work on those parts of the skeleton (pp. 146—148, Plate 
 XVII.) ; and now the rest of its skeletal structure is given in this Paper. 
 For the young of the Least Auk (Ciceronia pusilla) from Behring's Sea, I am 
 indebted to Frederic A. Lucas, Esq., Washington ; for the embryos and 
 adult of the Razor Bill, and the adult Puffin, I am indebted to my son, 
 Professor W. N. Parker ; for the embryo of the Black-necked Swan, to 
 Dr. Murie ; and for the cygnets of the White Swan, to the late T. W. 
 Pocock, Esq. The early stages of the Common Duck were obtained by me 
 during the spring of 1887; and in these the dates of incubation were 
 obtained. 
 
 For many years after the publication of my first two Papers on the 
 Osteology of Birds,* my attention was directed solely to the skull, that part of 
 
 * "On Balcemceps rex": Transactions, Zoological Society, vol. iv., Plates LX1 V.-LXVIL, 
 pp. 269-351 : and "On the Gallinaceous Birds and Tinamous " : ibid., vol. v., Plates 
 XXXPV.-XLIL, pp. 149-241. 
 
 EOYAL ntlSH ACADEMY. — CUNNINGHAM MEMOIRS, NO. VI. [l] 
 
2 Cunningham Memoirs. 
 
 the structure of the Vertebrata, the elucidation of which seemed to be my 
 proper task. Of late, however, I have strayed into a " by-path meadow;" 
 for the other parts of the organs of support promised me as much pleasure 
 and profit as the skull itself.* That promise has been fulfilled ; not one 
 word of it has failed ; and now I can only wonder at my own self-denial 
 in not drinking from these other springs for so many years. That 
 distinguished friend who first laid the yoke of the skull upon my shoulders, 
 also tempted me into this wider field of research. In Professor 
 Huxley's Paper "On Dinosauria and Birds, "f we have the following 
 remarks : — " If the whole hind-quarters, from the ilium to the toes, of a 
 half-hatched chicken could be suddenly enlarged, ossified, and fossilized as 
 they are, they would furnish us with the last step of the transition between 
 birds and reptiles; for there would be nothing in their characters to 
 prevent us from referring them to the Dinosauria. "J 
 
 The value of these remarks is not in the least diminished by any after- 
 thought of the reader ; yet it is true that they refer to the " hind-quarters " 
 merely. Put in its neck the bird resembles a Plesiosaurus ; and in its 
 head an Ichthyosaurus: moreover, there are various "remnants" in the 
 fore-quarters of a bird that, as it seems to me, can only be interpreted by 
 the light of the " paddle " of those aquatic reptiles. Hence I do not in the 
 least believe that an Iguanodon begat the fore-fathers of the humming- 
 bird. 
 
 The two families of birds whose morphology is treated of in the present 
 Paper are very distantly related. The Alcidse lie in the centre, so to speak, 
 of a considerable number of families of water birds, and are manifestly 
 related to the Grebes and Loons, Podicipedidse, and Colymbida>, birds that 
 seem to be, both sorts of them, the modified descendants of Marsh's 
 Hesperornis. However this may be, the Alcidas are quite as nearly akin 
 on one side to the Penguins as they are on the other to the Loons and 
 Grebes ; and there is this initial difficulty with regard to their relationship 
 
 * Sec "On the Wings of the Common Fowl": Philosophical Transactions, 18S8, Plates 
 LXII.-LXV., pp. 385-398. 
 
 f Quarterly Journal Geological Society, 1869, pp. 12-31. 
 % Loc. cit., pp. 30-31. 
 
Me. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 3 
 
 to any actual descendants of Hesperornis, that in that huge toothed bird the 
 pre-sacral vertebrae are all " cylindroidal " in their articulation ; whereas 
 the Alcida-, like the Penguins and the Gulls, have their dorsals " opistho- 
 ccelous." In this they are just a step above Marsh's Ichthyornis, which 
 has its pre-sacral in a very low stage, namely, " amphicoelous," a condition 
 that is not quite lost in the existing Laridae. To complicate the subject 
 still more, as if to keep the way of the tree of descent, Professor Huxley has 
 already classified the Alcidre and the Laridae together. They are put 
 with the Petrels (Procellariidoa), birds whose dorsals are cylindroidal, like 
 those of Hesperornis, the Grebes, and the Loons.* But the true position 
 and genealogy of the duck tribe (Anatidae) presents as tough a problem 
 as the auk tribe (Alcidae) ; we have, here, a faggot of tough problems, 
 that will task the ingenuity and strength of two or three generations of 
 biologists. 
 
 The structure of the skull in the duck-tribe is so similar to that of the 
 fowls, in all things at first, and in many things permanently, that I have 
 only taken up that part of the skeleton after it has acquired all the true 
 anatine characteristics, namely, in the nearly ripe embryo of Cygnus nigri- 
 collis. For I had long ago worked out the skull of the common fowl, the 
 early stages of which illustrate so accurately those of a duck, goose, or swan. f 
 The skull of the guillemot ( Uria troile), my example of an alcine skull, is 
 worked out as early as the third stage in the chicken (op. cit., Plate LXXXII.) 
 The swan's early stage corresponds with one between the fourth and fifth 
 stages in the chick (op. cit., Plates LXXXIIL, LXXXIV.). In the rest of .the 
 skeleton the more jDrimitive condition of the parts has been worked out in the 
 embryo duck. In these parts I have gone down far below the morphology 
 of the adult Iguanodon, and have, as I believe, unconsciously thrown some 
 light upon its development, for that huge beast was highly specialized. It had 
 got a long way from its amphibian ancestors : its size, as well as its 
 peculiar "hind-quarters," attest this. 
 
 * See his Classification of Birds, Proceedings, Zoological Society, 1867, pp. 457, 458. 
 f See Fowl's Skull, Philosophical Transactions, 1869, Plates LXXXL-LXXXVII. 
 pp. 755-807. 
 
 [1*] 
 
4 Cunningham Memoirs. 
 
 The Morphology of the Anatih^;.* 
 
 The Cranium in Cj/gnus. 
 
 The intense ossification seen in birds makes this part of the skeleton a 
 "closed book" in the adult; embryos, near the time of hatching, are the 
 most profitable for interpretation of the various parts, and for comparison 
 with what is found in the skull of other types. 
 
 The two extremes of cranial structure in those hot-blooded Sauropsida 
 are to be found, on one hand, in the Tinamou, which retains many of its 
 sutures, and has one, or even two, rows of supra-orbital scale bones ; and, 
 on the other, in a Passerine bird, where the metamorphosis of a skull, 
 essentially reptilian, lias reached its utmost perfection. 
 
 The ectocranium of the nearly ripe embryo of Cygnus nigricollis (Plate III., 
 figs. 1— G, and Plate IV.) has most of its sutures open, and remains of those 
 that arc closing. These bones are very massive for a bird, and have a 
 struthious coarseness about them : in the adult bird this is greatly altered 
 by the absorption of much of the diploe, for the sake of pneumaticity. 
 The facial splints, as compared with those of the chick, are very broad ; 
 for we have in these " lamellirostres " (or sifters) a spoon-shaped bill, not 
 ending insensibly in a more or less hooked point, but in a neat "unguis" 
 like a finger-nail, and adapted to the flatter part in the mandible, like a 
 thumb to a finger-nail in us. The premaxillaries (px.), as in osseous 
 fishes, dominate the upper face : they form three-fourths of the spoon- 
 shaped " rostrum," and are already ankylosed in the foremost third. 
 Unlike mammals, the bird has long "nasal processes" to its premaxil- 
 larium — long, narrow splints, that run backwards between the nasals, 
 and overlap the forehead. Laterally (Plate IV., p. n.) the dentary margin, 
 covered with a false dentition of horny lamina?, overlaps the maxillary (;».?-.), 
 and reaches to the jugal bar (,/., q. j-). The notch between these processes 
 is rounded, and a similar notch in the nasal (;?.) finishes behind a large 
 
 * See, on this subject, Dr. E. 0. Cunningham's Paper " On the Steamer Duck [Micropterus 
 rinereus) " : Ti ansactions, Zoological Society, vol. vii., Plates LV11I.-LXIL, pp. 493-501. 
 
Mk. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 5 
 
 oval space, in which is seen the alinasal folds (al. n.) and external 
 nostril (e. n.). Already we have come across two agreements between the 
 anatine and the gallinaceous skull, the hidden position of the maxillary 
 like its counterpart, the " os mystaceum" of the perch, and the large oval 
 space in which the nasal vestibule is exposed; these birds are both " holo- 
 rhiual." The AlcidaB, as we shall see, are " schizorhinal," the nasals not 
 being notched behind, but split. 
 
 In the Anatidos the fore-part of the skull is very peculiar ; the lachry- 
 mal or pre-orbital region is unusually long (see Plate III.). The nasals (n.) 
 have a very large frontal plate, and the " hinge " is in front of that plate, not 
 at the posterior edge of the nasal bones. They become thinned down and 
 elastic where the motion is recpiired. The lachrymals (7.) here attain their 
 greatest size, and have the longest suture above ; they then become nar- 
 row and are hooked backwards below, and help, by their hind margin, to 
 enclose the very open orbit. 
 
 In the fore palate the premaxillaries (see Plate III., fig. 1, p.v.) have 
 a short palatine process that binds upon the inner edge of the maxillaries 
 (mx.) ; the median region is taken up by the huge temporary prenasal 
 part of the intertrabecula (pi.); half the dentary edge is formed by the 
 maxillary, overlapped by the premaxillary ; each palatine process (or 
 maxillo-palatine, mx. p.) runs inwards and backwards, approximating, be- 
 hind, to its fellow ; and then, ending in a rough point, they diverge to embrace 
 the vomer at its thickest part. This latter bone is a flat vertical spatulate 
 plate, with its broad end behind ; pointed somewhat there, it is again fixed 
 between the sharp styloid "ascending processes" of the palatine (Plate 
 III., figs. 1 and 5, v., pa.). At present the vomer is only composed of 
 one centre ; another appears on the antero-superior corner afterwards 
 (Plate II., fig. 15, v.). The vomer, palatines, and pterygoids belong to 
 the mid-palate ; a pre-palatine bar, however, runs far forwards, wedged into 
 a deep notch in the maxillaries. These large, long bones (pa.) form the 
 lateral boundaries of the nasal passages, which open at their hinder part in 
 one common median " posterior nostril." Their widest part is near the 
 angle of the upper jaw ; they narrow in, sinuously, to their end ; they 
 approximate then, and send forwards and upwards their sharp ascending 
 
6 Cunningham Memoirs. 
 
 process. The "middle nasal openings" are between the vomer and the 
 palatines. 
 
 The next bones are the pterygoids (pff.). They are only one third the 
 length of the palatines, which are wedged into their fore-part below; whilst 
 the pterygoids form a peg in front, which is fitted into the upper face of 
 each palatine. This is a curious doubly-pegged joint, which is imperfectly 
 developed in the fowl tribe ; their palatines and vomer are very slender, 
 and the pterygoid peg is not so small and neat ; it is styloid. Nevertheless 
 these two families agree in having a truly azygous vomer, and in not having 
 this pterygoid peg segmented off and fused with the palatine, as in most 
 birds. Also in the small epipterygoid process of the pterygoid, in the 
 breadth of its fore end, and in the fact that it articulates with the basi- 
 pterygoid processes of the basis cranii at its front third, the geese and 
 fowls agree. For, in most birds, when these parts are developed, the 
 articulation is at the middle of the pterygoid : in the struthious birds, 
 Tinamous, and in the embryo of Opisthocomus, it is at the end. 
 
 Although the palatines and pterygoids, because of their histological de- 
 velopment, are here classed with the parts of the " ectocranium," they are in 
 reality degenerated einIo-crama\ tracts that have lost their cartilaginous pith. 
 
 Behind the palate, under the broad hind-part of the endocranium, there 
 are three tracts of parosteal bone that at an early stage became fused 
 together as one tract this bony growth is the " parasphenoid " ; the 
 three parts are the " basi-temporals " behind, and the " rostrum " in front 
 (Plate III., figures 1 and 5, pa.s., s., r.b.s., b.t.).* Of all birds the 
 fowls and the duck tribe have the basi-temporals most massive ; this is 
 well seen in the goose, and in Tetrao urogallus. The parasphenoid is 
 generally, not always, in one piece in the Ichthyopsida ; it sometimes 
 has a separate centre in front in certain frogs, f It grafts itself on the 
 basis cranii, aborting the cartilage, in some of the Urodela.J In birds 
 which have a certain amphibian stigma§ in many parts of their organization, 
 
 * Fowl's Skull, Plate LXXXIL, fig. 2. 
 
 f Philosophical Transactions (1881), Plates V. and VIII. 
 
 J Transactions, Linnean Society, series ii. (Zoology), vol. ii., Plates XVII. and XX. 
 
 § In the existing reptiles the parasphenoid is but little developed. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 7 
 
 this grafting of a " parostosis " on the basal cartilage, thus taking the place 
 of a normal endoskeletal bony centre, takes place very early ; and the three 
 primary centres, fused into one, support, in front, the interorbital wall, then 
 develop large " anterior tympanic recesses," and, behind, form most of the 
 thick but excavated basicranial floor (see Plate III., figs. 1 and 5, r.b.s., 
 b.t, a.t.r., and Plate IV.). The basi- temporal mass, a transverse tract 
 bulging forwards at the middle, lies on a lower plane than the fore-part ; 
 in a deep chink between the two masses, the eustachian tubes (eu.) converge 
 towards each other. 
 
 I have already spoken of the articulation of the basi-pterygoids with 
 the pterygoids ; this takes place in a remarkable manner,* for a new plate 
 of cartilage is developed on both bones ; in the Struthionidaef the pterygoids 
 acquire an articular plate of cartilage, but the basi-pterygoids are direct 
 outgrowths of the basis cranii, and their articular facet is formed by an 
 arrest in the process of ossification of the outgrowth, as in Lizards. 
 
 This shows how far the fowls and the goose tribe have travelled from 
 those archaic birds — the Struthionidae and their immediate allies. 
 
 The cheek, in this and most birds, is very feeble, and is funned of three 
 overlapping splints, the foremost of which is a mere outgrowth of the 
 maxillary, its jugal process. This is overlapped by a separate style of 
 the same size, the jugal (/.) ; and under and within these the quadrato- jugal 
 (q.j-) binds the whole together to the quadratum (>].) ; it is one-third 
 longer than the jugal, and is hooked inwards behind, where it is articu- 
 lated to the quadrate. These parts are true parostoses, and are extremely 
 unlike their broad counterparts in the Crocodiles and Tortoises, and in 
 Hatteria. 
 
 The roof-bones and temporal plates add three pairs more to the cate- 
 gory of parostoses; the foremost of these are the f rentals (/.), which are 
 the largest bones in the skull, and are yet extremely deficient above and 
 over the orbits. A large " fontanelle " still exists at the part where the 
 small hole is seen in Lizards — the orbit of their median eye ; in old geese 
 this fontanelle remains, sometimes bringing the bird near the Lizard, but 
 
 * Sec Fowl's Skull, he. cit., Plate LXXXIII. 
 
 f Philosophical Transactions, 18G6, Plates VII. -XV. 
 
8 Cunningham Memoirs. 
 
 the organ itself is very little developed in birds. The parietals (p.) are of 
 small axial extent in the Anatidse, as in the Ruminant and Cetacean 
 Mammalia ; they meet the frontals, are overlapped laterally by the squa- 
 mosals (•$'/.)> an( l overlap the supraoccipital (s. o.). 
 
 The squamosals (sq.) are roughly pentagonal bones that overlap the 
 frontals and parietals at their junction, binding the supraoccipital (s. o.) 
 behind, and forming an cave over the auditory recess. 
 
 The rest of the osseous centres belong to the endocranium. These are 
 transforming the massive " chondrocranium," a remarkable beaked struc- 
 ture, with a short, wide, cranial basin. This has to be described before the 
 bony tracts. 
 
 Much of this can be seen from below (Plate III., fig. 1), and has also to 
 be surveyed on its side (Plate IV.); its end (Plate III., fig. 3) from above 
 (Plate III., fig. 2), and in a section taken longitudinally and vertically, a 
 little to the left of the mid-line (Plate III., fig. 5) ; thus the crested and 
 rostrate fore-part is seen from its side, and not in section. The occipital 
 base, sides, and plane show that this part is a bulging and oblique hindwall ; 
 it also forms the hindmost part of the floor. The auditory capsules (cat.) 
 are very large, and are jammed in obliquely between the occipital arch 
 and the sub-transverse posterior sphenoids. 
 
 At present the notochord (nc) forms the axis of the basi- occipital bone 
 (5.0.) ; it has shrunk from its extension into the posterior clinoid wall 
 (Plate III., fig. 5, j>//-), and now forms only the axis of the hindmost 
 cranial segment. Right and left, it was enclosed in the " parachordal " 
 cartilages, which becoming alate laterally, and their wings meeting over 
 the myelon, formed also the hinder skull basin and its end wall, i.e. 
 alisphenoids (a.Ls.), exoccipitals (e. o.) and supraoccipital (s. <?.). 
 
 The proper axial skeleton, namely that related to and formed upon and 
 around the notochord, ended from the first behind the pituitary involution 
 of the oral membrane. The chondrocranium therefore is sharply divided 
 into a post-pituitary and a pre-pituitary region. Looking at these parts 
 from the standpoint of adaptation the pre-pituitary part seems to be a 
 morphological aftergrowth — almost like an afterthought. For in these high 
 skulls, as in the high skulls of many osseous fishes the fore-part of the skull 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 9 
 
 serves mainly as an orbitonasal wall, a partition run up between the eye- 
 balls behind and the nasal capsules in front ; in the bird, as in Cartila- 
 ginous Fishes, that which forms the middle part of the foundation of the 
 wall is carried forward as a long " pre-nasal rostrum." This part forms most 
 of the skeleton of the skate's large beak ; in the bird it is the temporary 
 model on which the secondary facial skeleton is formed. But the skate has a 
 low and the bird a high skull ; in the one the brain lies down on a flat 
 floor ; in the other it is tilted up behind and a little over the interorbital 
 wall (Plate III., fig. 5). 
 
 In this, as in other things, the bird is not the direct offspring of any 
 form that we know of : it has chosen this and rejected that, "wittingly," 
 so to speak; its feathers are a " new thing upon the earth." The space 
 between a lizard's scale and a peacock's train-feather is very considerable, 
 and I know of no hot-house and no manure that would "force" the one to 
 form the other. As far as to the hinder part of the septum nasi (s. n.) the 
 pre-pituitary part of the chondrocranium is formed of three rods : the 
 trabecular and intertrabecula (//•., i. tr.)* These parts are, as far as my 
 researches show, the oldest by far ; the cartilages that form right and left 
 of the notochord appear to me to be comparatively recent developments 
 of the cartilaginous supporting tracts. f Over the optic nerve (II.), mor- 
 phologically between it and the olfactory nerve (I.), the trabecular or 
 pre-pituitary wall shows a slight development of the orbito-sphenoids (o.s,). 
 Between the olfactory regions the nasal roofs are continuous with the 
 common orbito-nasal partition-wall ; and the median part sends backwards 
 a small crista galli (cr.g.). The roof is in three regions, namely, the " ali- 
 ethmoid " (al.e.) behind, the " ali-septal " (al.sp.) in the middle, and the 
 " ali-nasal " (al.n.) in front; the latter folds not covered with bone 
 (Plate IV., and Plate III., fig. 2, al.n.). The true olfactory region is short 
 and simple, and is walled in behind by a fold which corresponds to the 
 " pars plana " of human anatomy ; but there are no special " upper " and 
 " middle turbinals" in this and other Catenate birds. The inferior turbinals 
 
 * See Challenger Reports, " Skull of Green Turtle " : Zoology, vol. L, Plate II., figs. 6, 7. 
 f See my Paper "On the Harsipobranch Fishes" : Phil. Trans., 1883, Plates VIII.-XXVL, 
 pp. 373-453. 
 
 ROYAL IRISH ACADEMY. CUNNINGHAM MEMOIRS, NO. VI. [2] 
 
10 Cunningham Memoirs. 
 
 are scrolls of cartilage with from one and a-half to two coils ;* they 
 remain unossified as a rule.f In the generalized, archaic, and retrograded 
 Struthionidge the tnrbinals anticipate those of Mammals, and are extremely 
 complex.:}: Also in these birds§ the solid orbito-nasal partition is never 
 taken away in any part ; in the Carinata? it is removed, under the naso- 
 frontal transverse line, to form the cranio-facial hinge, a remarkable structure 
 peculiar to Carinate birds, and necessitated by the abortive develop- 
 ment and new function of the fore limbs. This departure from what is 
 typical is well shown in the swan's embryo (Plate III., fig. 5, c.f.c.) ; for 
 the " cranio-facial cleft" is now a large round notch and is quite similar to 
 what is seen in some species of those of undecided types — those Struthious 
 Carinatse, the Tinamous.|j The trabecule in their fore-part, and the inter- 
 trabecula at its hinder third have been roughly sawn across, so to speak, 
 and the wall, above, removed for three-fourths of its height. Here we have 
 a secondary segmentation of parts that in us are only marked off by the 
 different condition of the tissues, the "perpendicular ethmoid" being 
 ossified, and the "septum nasi" only partially calcified. Here the per- 
 pendicular ethmoid (p.e.) is already larger than the membranous space 
 that separates it from the septum nasi (s.n.). 
 
 The morphology of the " pre-nasal rostrum" (pn.) is evident: it is a 
 mere fore-growth of the intertrabecula, and in skates, saw-fish, and even 
 in some Ganoids it is often of great length. ^j If Ave look at the under 
 view (Plate III., fig. 1) and at a much earlier stage in the chick (op. cit. 
 Plate LXXXII., figs. 2 and 2a, p.n.) we shall see what use is made of it 
 in the bird, where it is first used, and then absorbed. It is more spatulate 
 in the swan's than in the fowl's embryo, being the model in the former 
 case of the large premaxillary spoon. 
 
 The brain is tilted up over the orbito-sphenoidal region, and lies low down 
 
 * Fowl's Skull, Plates LXXXIII. and LXXXYI. 
 
 f In Land and "Water birds. 
 
 % Ostrich's Skull, Plates X. and XII. 
 
 § Ibid., Plates VII. and VIII. 
 
 |! Ostrich's Skull, Plat,' XV., tig. 8 (c.f.c). 
 
 1} See "On Lepidosteus osseus " : Phil. Trans., 1882, Plate XXXVIII., fig. 1 (p.n.). 
 
Me. W. K. Paekisk. — Morphology of the Duck and the Auk Tribes. 11 
 
 in the broad hollow of the cupped hind cranium, the post-pituitary or 
 notochordal region. Here the chondrocranium is rapidly ossifying even in 
 this water bird with precocious young. But in those birds that have tender 
 young, the " Altrices," in which the Carinatse have many culminations, 
 the process is much more rapid, as are all these pre-nasal transformations. In 
 the wren {Troglodytes europcvus) at the twelfth day, when it is ripe for 
 hatching, it has had only half the time for development as this almost ripe 
 embryo of the swan, and yet it is as far advanced. Here in the case of the 
 wren we see the result of a veritable " forcing " process in a real, and not im- 
 aginary, "hotbed." The parachordal cartilages have formed a transversely 
 kidney-shaped occipital condyle (Plate III., fig. 1, oc.c), and the basi- 
 occipital bone (b.o.) is oblong ; it has not proceeded far right and left of the 
 notochord (no.). The ex-occipitals (e.o.) are multiangular plates, that are 
 margining the foramen magnum, and enclosing the outgoing hypoglossal, 
 vagus, and glosso-pharyngeal nerves (xii.). There is still a large cartilagi- 
 nous bed in which these bones lie ; at a distance above them, equal to their 
 breadth, we see the large double supraoccipital (s.o.). This bone has the 
 remains of its primary suture above ; it is shield-shaped, with the sides 
 deeply notched; this round notch half encloses the "lateral occipital 
 fontanelle" (l.o.f), which is finished by the squamosal and auditory capsule. 
 This structure is confined to the Grallaj, plovers and cranes, &c, and to 
 certain water birds — gulls (in which it becomes filled in afterwards), and 
 iVlcida?, besides these normal Chenomorphs. Here the goose tribe parts 
 company with the fowls, which have no such structure. The frail skull of 
 the lesser LimicolaB shows a notch above the foramen magnum, where the 
 two supraoccipital centres have not united. This notch tends to fill in in 
 the hemipods, but in pigeons and in owls it does not fill in, except beloAV, 
 so that a "middle occipital fontanelle " remains, a mere pin-hole like the 
 parietal orbit of Lizards, but assuredly without any such meaning as that 
 famous "sky-light"; so the mind of the morphologist is greatly exercised 
 as to the purpose of these closed-up windows. 
 
 Laterally, the posterior sphenoid has the main part of its wings ossified 
 as the alisphenoids (Plate III., fig. 5, a.l.s.) ; these are almost transverse in 
 this position, and form, indeed, the post-orbital wall. Not only so, they 
 
 [a*] 
 
12 Cunningham Memoirs. 
 
 send out a large spin- of cartilage (Plate IV., sp, o.), the " sphenotic process," 
 which, in some birds {e.g. owls), is ossified separately, and thus gives us 
 the remains of the large post-frontal bone (sphenotic) of an osseous fish. In 
 the old bird this might be taken for a post-orbital process of the frontal, or 
 for a rudimentary zygomatic process of the squamosal ; it is overlapped by 
 those parts, but belongs to the endoskeleton. I find no other Vertebrates 
 except the Urodelous amphibians that anticipate the peculiar development 
 of the basi-sphenoid of the bird. The basal bars that unite to form the main 
 beam in a reptile are ossified intrinsically. The bird, like the Urodela, has 
 no distinct " basisphenoid " ; but the cartilage borrows its bony matter from 
 the hind part of tlie median parasphenoid, after which it runs forwards, free 
 from the cartilage, as the " basisphenoidal rostrum" (Plate III., fig. H,pa.). 
 Once the ossification overtakes the cartilage round the pituitary space {p>/), it 
 runs rapidly into the floor of the skull behind, and right and left. Together, 
 this grafted bone, and the superficial growths — which form the anterior 
 tympanic recesses, and the basi-temporal plate — produce in the bird, whose 
 skull is so thoroughly pneumatic, very complex tympanic outworks, as 
 complex as those of the crocodile,* but of a different type. 
 
 As in those osseous fishes that have a high skull, the pituitary floor is 
 open; it is finished by the parasphenoid ; the internal carotids (i.e.) enter 
 the skull through this space, creeping over the basitemporal plate, whose 
 diplbe forms a bony tube for each artery. At present the pinched-up 
 anterior sphenoid (o. s., p. s.) is unossified ; but the perpendicular ethmoid 
 (p. c.) is a large slab of bone behind the notch for the hinge, larger than 
 the notch. The auditor)/ sense-capsules, like the olfactory, are built into the 
 cranium, and have to be described as parts of it, although they have no 
 original right to this position. These parts are very large, and each carti- 
 laginous capsule, which is planted like a bulb in the side wall of the hind 
 skull, soon coalesces with the proper cranial walls. These oval capsules 
 are tilted backwards, so as to lie supine, and almost in a horizontal position 
 (Plate III., fig. 5). The upper part of each capsule is occupied with the 
 three semicircular canals (a. s. c, p. s. c, h. s. c), and under the arch of the 
 anterior canal there is a recess like that for the "flocculus cerebelli " in 
 * Transactions, Zoological Society, vol. ii., 1'latcs LXII.-LXXI. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 13 
 
 the Mammal. The hyena, or rudimentary cochlea, is buried in the basi- 
 latcral cartilage (Plate III., fig-. 1) over the hind edge of the basitemporal 
 plate. The recess, or " meatus interims " for the seventh and eighth nerves 
 (vii., viii.) is shallow, the meatus externus is membranous and very short, 
 and the tympanic cavity is formed by the utilization of many parts round the 
 primary tympanic (or 1st) clef ((see Plate IV.). In front, the large quadrate 
 bone (q), mistaken by our ancestors for the tympanic, and mistaken for it still 
 by those who are not cmbryoloyists, forms the front wall of the porch. Its floor 
 is formed by the basitemporal, its inner wall by the auditory capsule, and 
 its roof and sides by the squamosal. Sometimes there is one, sometimes 
 more than one, six even, true tympanic bones.* I find no separate tympanic 
 in the Anatidae ; but in the duck the floor and sides approximate, closing in 
 the cavity, all but a narrow chink ; this structure is seen still better in the 
 green woodpecker ( Gecinus viridis).~f In that bird this secondary tympanum 
 is like a small Cowrie shell [Trivia). Pound the meatus interims ^ Plate III., 
 fig. 5, vii., viii.) a considerable oblong bone, the periotic (pro.), is already 
 formed; the opisthotic (op.) is seen behind and below; a chink separating 
 it from the exoccipital (e. o.) ; it is a much smaller bone ; externally it joins 
 the delicate bar that separates the fenestra ovalis from the/, rotunda. The 
 epiotic is not seen here, and is rare in birds. 
 
 There are three visceral arches developed in a bird ; the palatine extension 
 forwards — a part of doubtful morphology — I have already described as the 
 pterygoid and palatine membrane bones : bones that had no true cartilaginous 
 model. The proper pier of the mandibular arch, the quadrate (q), is well 
 developed ; it is much more like that of an amphibian than the quadrate 
 of a serpent or a lizard. It is indeed developed distinctly from the chon- 
 drocranium, and does not coalesce with it at any part ; but it has a large 
 " pedicle," or orbital process, and a large " otic process " with two condyles, 
 as in the Peristeropodous Gallinaceous birds, and in most of the Carinatse. 
 The quadrate has already a large bony shaft ; the pedicle and the articular 
 regions are still soft. That bone corresponds to the upper piece of a 
 branchial arch, with only two segments; that is its true nature: it is 
 
 * Transactions, Zoological Society, vol. ix., Plates LV., in Corvus corone. 
 
 f Sec Transactions, Linnean Society, second series (Zoology), vol. i., Plate II., fig. '2. 
 
14 Cunningham Memoirs. 
 
 a " pharyngo-epihyal." The core of the mandible is a cerato-hypohyal 
 (Plate IV. and Plate III., fig. 4, ar. mlc). Here let it be noticed that the 
 posterior and internal angular processes (p.a.p., i.a.p.) are parts of this 
 " articulo-meckelian " bar; these processes are unusually developed in the 
 cultrirostral fowl, and in these lamellirostrcs, also in that lamellirostral 
 relation of the Ibis, the Flamingo. The cartilaginous rod (mk.) runs inside 
 the dentary splint (d.) nearly to its end; and the kinship of the trabecule 
 to the visceral arches is nowhere more plainly suggested than in this stage 
 of the bird ; that, however, is a knotty problem. There are two layers of 
 bone covering this rod, a deep and a superficial layer. The deep deposit is 
 the ectostcal " articulare" ; its endosteal part has not yet appeared; the 
 superficial or parosteal bones are the dentary (</.), the splenial (sp.) ; the 
 supra-angulare (s.ag.) and the angulare (ay.). I find no coronoid in this 
 family, nor in the GallinaceR3 ; otherwise it is quite like the mandible of a 
 reptile ; the coronoid does turn up in the Passeres, and in some Grallaj. 
 
 The liyoid arch of this, as of other birds, is essentially reptilian. Its 
 " pharyngo-branchial" element is, at first, quite separate from the rudiments 
 of the rest of the arch. All those Vertebrata that have a fenestra oralis 
 have the pharyngo-branchial element of the second visceral arch modified, 
 as a stapes or columella. This may be severed from or united with the 
 other segments of that, the hyoid arch. In the Hatteria, and for a time in 
 the Crocodile, these parts become united : in the bird they also unite, and the 
 arrested sub-apical or epi-hyal element remains continuous (confluent) with 
 the stapes. It is generally very small, but sometimes shows a dilated 
 ccrato-hyal tract. In the crow,* in the fowl,f and in the Anatida?, Alcidre, 
 and many others, it varies very little, and is extremely small and slender. 
 
 The distal part of the hyoid arch (Plate III., fig. 6), below the aborted 
 membranous tract, is mainly hypo-hyal ; but that is not a separate seg- 
 ment, and the term for this partis still " cerato-hyal " (c. liy.) ; the two, 
 right and left, coalesce in front, and almost separate off a true basi- 
 hyal. This lingual skeleton is very large in these Anatidse. The third 
 
 * Transactions, Linnean Society, series ii. (Zoology), vol. 1., Plate XX., figs. 8, 9. 
 f Fowl's Skull, Plate LXXXVIL, fig. 3. 
 
Me. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 15 
 
 visceral arch, corresponding with the first branchial arch of an osseous fish, 
 is composed of two segments (br.), nearly equal in length. The lower of 
 these is almost ossified. The upper in these birds is thick below ; and the 
 thick part is flat above. This is very characteristic of the duck tribe. 
 There is a basal piece of cartilage, thick in front of the articulation of the 
 third visceral arch, and slender behind ; the fore-part of this (bh. br.) 
 corresponds with the first basi-branchial of an osseous fish ; the hind-part 
 with the second, and even third. 
 
 In a nestling cygnet of the common swan (Cggnus olor), fourteen inches 
 long, and presumably three or four weeks old, the skull as seen in section 
 (Plate V., fig. 1) shows a great advance in development as compared with 
 the almost ripe embryo. The superficial bones are still distinct, but they 
 meet well together now, and are acquiring their permanent form. The 
 frontals (/.) are still very thin ; but they and the short parietals (p.) have 
 obliterated most of the great upper fontanelle of the embryo. A small 
 triangular patch of the squamosal (sq.) can be seen inside the skull. In 
 front the premaxillaries (px.) are fused together, except in their thin nasal 
 processes ; and their core, the prenasal cartilage, is now absorbed : they 
 soon after this become fused with the maxillaries. The basi-sphenoidal 
 rostrum (pa.s.) is still free from the base of the intcrorbital septum, 
 except behind; and, further back, the basi-temporal plate (b.t.) shows its 
 independence of the basis cranii proper. The perpendicular ethmoid (p. e.) 
 forms the hind boundary of the hinge notch (c.f. c). It has reached the top 
 of the plate, where the aliethmoidal folds are given off ; and behind it 
 reaches the small intcrorbital fenestra (/. o. /.). Below, it only reaches to 
 the trabecular beam, which projects a little in front of it, and is then lost 
 for a space ; this beam reappears under the irregular septum nasi (s. «.), but 
 all the pre-rostral part in front has disappeared. Where the septum nasi 
 leans forward above, giving off the ali-nasal folds, there an oval space is seen 
 under it, finished below by the bones of the face. This is often seen in 
 water-birds as an open window between the right and left nostrils. The 
 alisphenoids (al.s.), the borrowed basi-sphenoid (b. s.), the basi-, ex-, and 
 supra-occipitals (b. o., e. o., s. o.) are all well develoi)ed, and are only divided 
 by a narrow tract of cartilage. The small opisthotic {pp.) clings, now, 
 
16 Cunningham Memoirs. 
 
 close to the large prootic {pro.); the epiotic is replaced by a large ingrowth 
 from the supraoccipital (s. o.). The passages for the outgoing nerves (i., 
 ii., v., vii. , viii., x., xii.) can be seen well in this view. 
 
 In a gosling (Anser palustris, domesticus) six weeks old I found the 
 well known antcro-superior spine of the vomer in a separate condition 
 (Plate II., fig. 15, v., vi.). In the adult black swan ( Cygnus atratus, Plate II., 
 fi°\ 14, pa.,i.pa.) I found a pair of inter-palatine bones that tend to 
 make this bird doubly desmognathous. The same milioline bones are 
 often found in the Ducks (Anatida?).* 
 
 In the old Cygnus olor, as in Chauna chavaria, the forehead becomes 
 largely swollen and pneumatic, and the lachrymals, fused with the frontals, 
 are extremely large and swollen; the sphenotic process also being very 
 large, these parts nearly meet below the orbit. In Dendrocygna acuta these 
 processes do meet and coalesce; thus a suborbital bar is formed, like that 
 which is seen in most of the Psittacida?. 
 
 In the old white swan [Cygnus olor) the lateral occipital fontanellcs 
 become filled in with periosteal bone : in an old black swan (Cygnus atratus) 
 I find them open but small. 
 
 The interorbital fenestra becomes filled in in the swans ; and in the 
 common species this part is very thick and spongy. 
 
 There arc several kinds of birds that have a dentatcd horny mandible : 
 none outside the Anatidse have the " quaff ering organ" perfect, except 
 the Flamingo, a " Pelargomorph." But the archaic Chenomorphse — the 
 Palamedidse — are cultrirostral, and have a beak similar to that of a fowl : 
 they look downwards in the direction of the Gallinaceous Root ; and the 
 Peristeropodes of the same region, like them, become desmognathous. We 
 should have to travel far back, however, before we came to the meeting- 
 place of these two types. Within the bounds of the Anatidae, proper, the 
 bill varies extremely in width : the two extremes are the Merganser (Mergus), 
 and the Shoveller (Spatula clypcata).^ 
 
 * See Wiederslieirn's Comp. Anat. of Vertebrates : Translation by W. N. Parker. 
 Maeniillan & Co., 1886 : p. 79, tip.-. 65, B. pi. 
 
 \ See Sbnfeldt " On the North American Anseres " : Proceedings, TJ. S. Nat. Mus., vol. 11, 
 pp. 215-251, fig. 2, p. 218, anil fig. 10, p. 232. 
 
Mb. W. K. Parkeij. — Morphology of the Duck and the Auk Tribes. 17 
 
 On the supposition that the cold- and hot-blooded Sauropsida — reptiles 
 and birds — have arisen, during time, from a similar (or the same) amphibian 
 platform, this one family (the Anatidse) is sufficient to show what the mor- 
 phological force can effect when working on teleological lines. 
 
 On the Development of the Vertebral Chain in the Anatidee.* 
 
 In the present Paper I shall deal with that in which these birds differ 
 from the Fowl tribe. The earlier stages have been worked out in the 
 chick, and the results will be published, at an early date, elsewhere. 
 
 On the Vertebral Chain in Cygnus nigricollis and C. olor. 
 
 In the advanced embryo of Cygnus nigricollis (Plates III. and IV.) the 
 vertebra? are in what may be called a Reptilian stage ; the osseous centres 
 are still distinct. The swans, however, although they are the true nobility 
 of the tribes of the water-birds, are yet remarkable for the retention of some 
 Reptilian characteristics. This is true as to the great length of the chain, 
 and also because of the presence of ribs up to the occiput. This is also seen 
 in the large Ratitae; but even the largest existing form — Struthio — has not so 
 many vertebrae, by ten, as the common swan. On the other side of the Class, 
 the specialization of this chain by the suppression of possible links or segments 
 is seen in the multitudinous lesser Passerines, and in swifts, humming- 
 birds, and other Coccygomorpb.se. More than half of the twelve thousand 
 species known have, on an average, only forty vertebrae, even in the embryo. 
 The African ostrich has ffty-si.v,^ and the common swan sixty-three. Nume- 
 rical law is not very strict in birds ; yet those six thousand species just 
 mentioned have in a great majority just fourteen cervicals, or twice as 
 many as in Mammals. Twelve also is a common number for the avian 
 sacrum in the small high-type birds ; and from ten to tioelve vertebrae in the 
 caudal region is as a rule the number in the embryo. In this embryo there 
 
 * For an account of this part of the skeleton in birds generally, see Proceedings, Eoyal 
 Society, 1888, pp. 465-482. 
 
 f See Mivart, Transactions, Zoological Society, vol. viii., p. 430. 
 
 R0TAX IRISH ACADEMY. CUNNINGHAM MEMOIRS, NO. VI. [*3j 
 
18 Cunningham Memoirs. 
 
 are twenty-tw o sacrals and twelve caudals : there are/ye dorsals in swans — 
 a common number. But in the same bird, on the two sides, the number of 
 lower cervicals that have free ribs, the number of dorsals, and the number 
 in the secondary divisions of the sacrum — all these things are variable 
 to a remarkable extent. 
 
 As to the adaptive modifications of the several links of this beautiful 
 chain, there is nothing like it in the class to which we belong. Birds 
 "seal up the sum" of adaptive modification of these intercalary segments 
 of the vertebrated organism. 
 
 In the cervical region C. nigricollis has one less than the common swan — 
 only twenty -four. The first two of these (the "atlas" and "axis") are 
 less perfectly ossified than most of those that follow; but in these the two 
 moieties of the neural arch are ossifying, and in the axis, its oivn centrum, 
 in the hinder part of the body. I shall explain this in the next stage. The 
 third to the eighteenth inclusive have a bony tract in their rudimentary 
 ribs. The last two, the twenty-third and twenty-fourth, have segmented 
 styloid ribs that are fast becoming bony. Much, however, of each vertebra 
 is cartilaginous ; and the notochord (on which these rings are strung — 
 through their base, not through their canal) is still of considerable size. 
 
 But the type of these vertebras is already established. They are 
 " cylindroidal" or " heterocoelous " ; so are all the pre-sacrals. The 
 cartilage, but not the bone, has met over the neural canal. The riblets that 
 protect the vertebral arteries, half-filling in their long burrowing passage, 
 were, for an extremely short period, distinct as cartilaginous points, as I 
 shall show in another Paper. They now connect the " diapophyses " with 
 the "parapophyscs" — the upper and lower " transverse processes"; and all 
 distinction of parts is lost up to the twenty-second vertebra. The styloid 
 part of these costal " remnants" is lost in the nineteenth and the three next 
 vertebras ; and in this stage the osseous centre has not yet appeared. These 
 birds are remarkable in that the axis only has an upper and lower spine. 
 In the third both are obsolete : the upper, even, is a mere ridge. This is 
 remarkable ; for of all birds the swan has the longest neck, and moves it 
 with most variety and grace ; moreover, in grazing and quaffering it uses 
 considerable force. Nor is there any closed inferior arch for the carotids 
 
Mr W. K. Parker. — Morplwlogij of the Duck and the Auk Tribes. 19 
 
 in these types, such as is seen in the heron and its congeners, long-necked 
 birds, but in which the length is gained rather in the individual vertebra 
 than in a great number. In the lower part of the neck the neural arch 
 gradually becomes crested, thus approximating to the dorsal region : a 
 feeble keel also appears below. The rather long cervicals increase in 
 their width, gradually, until they reach the large wide dorsals : near 
 them they shorten. The facet for the " tuberculum " of the free ribs 
 gradually creeps upwards so as to fit under the end of the large transverse 
 process: that for the " capitulum " is a raised oval basin near the fore 
 margin of the projecting articular part of the centrum. In these things the 
 dorsal vertebras agree with the two last cervicals. The spine is now a large 
 obliquely oblong up-growth, and the upper transverse processes are very 
 wide : they all have a slight lower spine, which becomes feeble in the last, 
 and is nearly obsolete in the first sacral (dorso-sacral). 
 
 Amongst the other Carinatas there is no such sacrum as this of the 
 swan ; it is nearly twice as long as in the multitudes of small and high- 
 class birds. Here, in this embryo, there are twenty-two vertebras (Plate 
 IV. and Plate III., figs. 9, 10) enclosed between the ilia, and indeed the 
 next, or first caudal is partly between those plates. 
 
 Here ossification is confined to the basal region ; the sheath of the 
 notochord has acquired twenty -two bony rings ; and the osseous matter has 
 crept into the investing cartilage, right and left ; in the true sacral region, 
 where the vertebrae are very short and wide, the deposit is bilobate ; there 
 are not, however, two separate centres, for each centre begins round the 
 azygous notochordal axis. The great Avian sacrum has four regions, 
 namely, the dorso-sacral with four vertebra;, the bimbo-sacral with three ; 
 the sacral, proper, with four, and the uro-sacral with eleven. 
 
 The spines are never quite obsolete, but are highest at the two ends 
 of the series ; the fourth dorso-sacral has half-developed ribs, to which 
 belong half -grown sternal pieces below (Plate IV.). The three lumbo- 
 sacrals have only thick, short diapophyses, buttressing the pre- ilia ; the next 
 four, or sacrals, proper, have these abortively developed in their lower 
 part. Prickles are seen in the last two, however, and these are remnants 
 of ribs. This is seen in the two next or first two uro-sacrals, where they are 
 
 [3*] 
 
20 Cunningham Memoirs. 
 
 separate bars, and become separately ossified like their several homologues 
 in the neck. The rest of the uro-sacrals have only diapophyses ; all these 
 in the true sacrals and uro-sacrals, are pedate or dilated where they arti- 
 culate with the ilia, and being broad, proximally, they thus leave a round 
 space, which is rilled with the corresponding ganglion of the "posterior 
 root" of the sacral nerve (y. ). Both in the lumbo-sacral, sacral, and uro- 
 sacral regions there is, in an earlier stage than this, an abortive attempt at 
 forming more ribs than remain, even as remnants, for in the embryo of 
 the common cluck I find the first five uro-sacrals with rib-bars ; the last 
 three of these, however, are soon lost.* In these vertebrates the meta- 
 morphosis of the organism is not confined to a certain strict term, as in 
 insects, but goes on for a long and, indeed, indefinite time ; the " Anura" 
 show this to a lesser extent. The diminishing scries of vertebra^ that form 
 the skeleton of the tail (cd. v.) has its transverse processes longest in the 
 middle ; its spines arc low and broad, and the third has, beneath, a small 
 intercentrum which passes under the second : there arc seven of these 
 milioline cartilages. In this specimen there are six free simple vertebra?, 
 and in the uropygial part six more ; the last of these segments, however, is 
 merely the naked end of the notochord (nc.) sticking out; it does, however, 
 become clothed with cartilage, and then converted into bone. At first the 
 uropygial piece (region) is formed, as a rule, of six segments; long ago, 
 however, in the winter of 1842—3 I found in a recently-hatched common 
 duckling ten osseous centres in a row in this part (Plate II., fig. 12). This 
 was, most likely, due to domestication. Like the overgrowth of digits in the 
 foot of the Dorking fowl, it is a proof of the exquisite sensitiveness to 
 surroundings that exists in these types. 
 
 Of the distinct and functional ribs in this embryo seven had perfect 
 sternal pieces ; the eighth pair were nearly perfect ; their lower bars were 
 not ossified ; the rudimentary ninth piece was far from its arrested upper bar; 
 the ribs were rapidly ossifying; the long last cervical, and four at least 
 (generally in swans the fifth also) have appendages (c.«.), cartilaginous 
 tracts growing from the middle of the rib, at its hind-edge, and overlapping 
 
 •'•' See Proceedings, Royal Society, 1888, \>. 47'J. 
 
Mr. W. K. Paekee. — Morphology of the Duck and the Auk Tribes. 21 
 
 the next following rib. The .sacral and caudal regions of embryo clucks in 
 earlier stages than this (Plate II., figs. 1-3) will be described with the hip 
 girdle. 
 
 In the second stage cygnets of G. olor, fourteen and fifteen inches long, 
 and about a month old, there are many important changes to be noticed in 
 the vertebral chain . 
 
 In the atlas (Plate V., figs. 2, 2a, 3, at.) the two centres of the neural arch 
 are united above, and a considerable deposit of bone has taken place in the 
 base; that basal piece, however, is not the true centrum, but an occipito- 
 atlantal " inter- centrum " (i.e.). The centrum, proper, of the atlas has 
 become fused with that of the axis {ax.) to form its odontoid process, as in 
 us ; it is now a considerable bony mass inside the thick odontoid pivot of 
 this peculiar cranio-vertcbral articulation. The atlas is proccelous, but in 
 most land and water birds the cup is deeply notched for the pivot; in 
 many of the nobler arboreal birds the cup is complete, save for a small 
 hole through which the odontoid ligament passes to tie the process to the 
 basis cranii. 
 
 The back of the atlas fits to the front of the axis by an almost flat-faced 
 joint, but this is not an articulation of centrum with centrum, but of the first 
 and second inter-centra dislocated in some degree through the arrest and 
 tilting of the borrowed atlantal centrum or odontoid process. Under and 
 behind that process, in that part of the base of the axis which binds on to the 
 atlas below, another inter-centrum is seen ; whilst the proper centrum (c.) 
 of the axis is behind both the bony tracts seen in this second vertebra. Only 
 post-zygapophyses are seen in the atlas, both pre- and post-zygapophyses 
 in the axis and all the rest of the pre-sacrals. Also the hinder face of its 
 centrum fits on to the next in the same manner as all the remainder of the pre- 
 sacrals; the joint is " cylindroidal," the centra seeming to be convex behind, 
 whilst in reality they are concave. A vertical section (fig. 2a) corrects what 
 the horizontal section (fig. 4) seems to show ; of course we have the exact 
 opposite of this in the fore-face of each centrum. Thus the fore-face of a 
 normal ornithic centrum, as is well seen in wide, flat vertebra 3 , is a convex 
 condyle that rolls in the rounded groove of the one in front of it. This 
 joint, assisted by the yoking processes or zygapophyses, allows, with perfect 
 
22 Cunningham Memoirs. 
 
 safety to the myelon, a very considerable amount of mutual movement 
 between vertebra and vertebra. But this is only part of 'this delightful 
 piece of animal mechanics. There is an annular meniscus interposed between 
 the contiguous cartilaginous surfaces in this synovial joint (fig. 4) ; and this 
 part being annular allows the suspensory ligament (s.l.) to pass from one to 
 the other; this ligament is nothing more than the old notochord. 
 
 But even this is not a full account of the care with which nature has 
 provided for the bird, in the structure of its neck — which is indeed its one arm. 
 As I have already mentioned, the vertebral arteries burrow their way along 
 the sides of the centra in the neck ; and behind the axis, in all birds, the 
 riblet finishes a tunnel right and left at the fore end of each vertebra. Here, 
 as in the great Ratita?, the topmost cervicals, the atlas and axis have, like 
 so many reptiles, ribs up to the occiput. There was no bony riblet in the 
 first stage (Plate IV.) ; here, in these cygnets, there is a small ossification 
 right and left on both these bones. 
 
 That on the atlas (figs. 2, 3, c.r. 1 ) is a short needle of bone formed in a 
 costal part of cartilage that had become imperfect. That on the axis 
 (fig. 2. c.r. 2 ) isquite normal, like those that follow : it is a bony wedge pointing 
 backwards, and is part of the costal band that ties together the upper and 
 lower transverse processes. 
 
 I have mentioned that in the herons and some other birds there is an 
 anteroinferior bridge to several of the cervicals (6 or 7) for the protection 
 of the carotids. The ribs do not fasten their " capitulum " between two 
 centra, as in us ; and they have a synovial joint for both capitulum and 
 " tuberculum." The latter is a gliding, the former a cup-and-ball, joint 
 (Plate V., fig. 4, r., e.). 
 
 Thus everything in the skeleton of birds is carried to its uttermost 
 perfection. They, not we, are, in respect of bodily movements, the crown- 
 ing forms of creation. 
 
 The dorsal vertebrae differ little from the last cervical (Plate IV., c.r., 
 d.v.): the primary dorsal region, however, has been largely taken in, to form 
 the fore-part of the long sacrum (Plate V., fig. 11): the avian sacrum is 
 four regions in one. 
 
 Finding how close the Anatidse come to the Ratitse in many things, 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 23 
 
 notwithstanding their aquatic habits, and feeling sure that the very term 
 " Ratitaa," as ordinal, is a mistake — a misleading term — I shall now show 
 how near these forms, the duck-tribe and the ostrich-tribe, come together in 
 the structure of their vertebral chain. Both have cylindroidal pre-sacrals, 
 and both have ribs on the atlas and axis. Finding (from my son, Professor 
 T. J. Parker*) that the intercentra of the atlas and axis were the same as 
 in the Carinatas, I looked for them in a ripe embryo of the rnooruk 
 (Casuarius Bcnnetti).^ That embryo is as large as the cygnets a month 
 old, and as much developed: its three foremost vertebra; (Plate IX., figs. 
 13—15) and its pelvis % show this. 
 
 The sectional view (Plate IX., fig. 15) shows that the odontoid process 
 (od. p.) leans over the atlantal intercentrum (i.e.), and is scooped below 
 where that intercalary element fits in. Then, again, by a remarkable 
 adaptation the second intercentrum (i.e.) comes close behind the first; and 
 the proper centrum of the axis only forms two-thirds of that compound 
 vertebra. The two opposed intercentra are narrow transverse plates of 
 bone, half as wide across as the contiguous centra. The cartilage is 
 imperfect over the vertebral artery in the atlas (at.), and the riblet is not 
 yet ossified: that on the axis (ax.) is also small, at present, but is embedded 
 in cartilage : that on the third (c.v. 3.) is much larger. The common Casso- 
 wary§ has no ossified atlantal rib, nor has the Rhea ;|| but the Emu ^] lias it 
 well marked on both sides. In Stmlhio** it is seen on one side only. So 
 that in these forms the atlantal ribs are less constant than in the Anatidse ; 
 and it is worth noticing that in the swans the sacrum has one or two 
 vertebra? more than in the giant African ostrich, which has only twenty. -\\ 
 The sacral vertebras of the cygnet (Plate V., fig. 11) do not correspond with 
 
 * An exhaustive memoir on the morphology of the Apteryx has been prepared by him, and 
 will see the light, in the Philosophical Transactions, as soon as the present Paper, 
 f See Zoological Transactions, vol. iv., Plate LXXIL 
 J Philosophical Transactions, 1888, B., Plate LXV., figs. 8-10. 
 § Mivart, Transactions, Zoological Society, vol. x., p. 28, fig. 23. 
 || Ibid., p. 3, fig. 3. 
 f Ibid., p. 17, fig. 14. 
 ** Ibid., vol. viii., p. 388, fig. 2. 
 ff Ibid., Transactions, Zoological Society, vol. viii., p. 420. 
 
24 
 
 Cunningham Memoirs. 
 
 what I find in very old specimens. I will therefore give the vertebral for- 
 mula of each of my stages : — 
 
 — 
 
 C. 
 
 D. 
 
 D. S. 
 
 L. S. 
 
 S. 
 
 U. S. 
 
 Cd. 
 
 Cygnus nigricollis, embryo 
 
 '24 
 
 5 
 
 4 
 
 3 
 
 4 
 
 11 
 
 G + 5 
 
 ,, olor, one month old . 
 
 25 
 
 5 
 
 3 
 
 4 
 
 4 
 
 in 
 
 6 + 5 
 
 olor, aged .... 
 
 25 
 
 5 
 
 4 
 
 3 
 
 4 
 
 10 
 
 7 + 5 
 
 Thus, whilst the two first have sixty-two vertebra? in all, the third has 
 sixty-three ; and there is a difference in each case as to the number in the 
 different regions. A little overgrowth of bony deposit, in the case of the 
 black-necked swan, would give it twenty-three sacrals, as its first caudal is 
 partly between the ilia. This great number of vertebra? in the Cygnince 
 may be adaptive : it is manifestly Reptilian. 
 
 The great length of the thorax in these heavy wide-bodied birds has 
 necessitated the development of three or, mostly, four pairs of ribs in the 
 dorso-lumbar region : in a large number of birds there is only one pair. 
 The gentle manner in which the individual vertebra? are modified as they 
 pass from one region to another is well seen in this stage (Plate V., fig. 11). 
 The lines of fusion of the vertebral elements in the embryo are still cartila- 
 ginous: where the uro-sacral region begins there two pairs of separately- 
 ossified riblets (s.r.) are seen below the corresponding diapophyses. I find 
 three pairs in Casuarius Bennett i * in which only two pairs of ribs are de- 
 veloped in front {Joe. eit. s.r.); but these two sacra are very similar, and the 
 same number of vertebra? are enclosed by the ilia in both cases. In the 
 mooruk (Casuarius Bcnnetti), however, the first of these retains its distinct- 
 ness as a dorsal vertebra. 
 
 The arrested and somewhat retrograded Ratitse show their loss of parts 
 and want of specialization in the caudal region. Mivart (op. eit., p. 430) 
 gives ten as the number of caudal vertebra? in the ostrich. I find only 
 eight in the mooruk. The same abortive condition of this part is seen 
 
 * Philosophical Transactions, 188S, B., Plate LXV., fig. 8, *. r. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 25 
 
 in the Tinamous ; but in the Anatidse, as in most Carinatae, and especially 
 in certain arboreal birds, it is a highly developed or greatly specialized* 
 part ; for the two first moveable joints in the caudal series become pro- 
 ccelous, and also acquire a joint-cavity. This is partly perfected in the 
 swan, but is best seen in such birds as the horn-bills : the rest of this 
 series is gently amphicoelous ; the two contiguous facets are joined together 
 by fibro-cartilage. The nobler Carinatse with strong " rectrices," or tail- 
 quills, have intereentra in this region to give greater purchase to the 
 " depressor coccygis."")" In the cygnet (Plate V., figs. 5, 6, 11, i. c.) I find 
 eight of these milioline cartilages : the last three of these belong to the 
 uropygial series : the three in the middle are the largest. These figures 
 show how strongly these unfused caudals are like those of the Ratitse: in the 
 swans and their congeners their number is greater ; and the uropygial 
 piece is a highly specialized region. 
 
 In the adult the cervical vertebrse have a notable structure. From the 
 third to the eighteenth inclusive, the re-entering angle between the neural 
 arch and the retral styloid rib is largely filled in by a secondary bony 
 lamina : thus the canal for the vertebral artery is walled in altogether in 
 from half to two-thirds of its extent : behind, in each vertebra, the outer 
 wall remains membranous. At the lower end of this series this plate is 
 separated by a fenestra from that part of the wall which is formed by the 
 open part of the riblet : thus, there is a delicate " flying buttress " running 
 obliquely upwards and backwards from the riblet to the neural arch — a 
 very elegant structure ; and, in this manner, the canal is often protected, 
 notably in the Cuculine types. In the swan and its congeners the wall is 
 completest ; and any cervical vertebra of a bird of this kind is easily 
 recognized. 
 
 All the vertebras of the swan are pneumatic, except the caudals : the 
 cervicals, except at the two ends, are elegantly oblong, depressed more 
 than usual, and narrowest at the beginning of the post-zygapophyses. 
 The huge dorsals have ossified tendons on their spines and diapophyses. 
 
 Altogether, this is one of the neatest groups of the Class ; but as the 
 
 * See Proceedings, Koyal Society, 1888, p. 472. 
 
 f See Macgillivray, British Birds, vol. 1 , p. 46, fig. 6. 
 
 HOIAL HUSH ACADEMY CUIsTflXGHAAl MEMOIRS, NO. VI. [4] 
 
26 Cunningham Memoirs. 
 
 old sorts of the Chenomorphse are not all extinct, the Palamedidse still 
 lingering' in the neotropical region, the classification of these birds is upset, 
 and the hedge set about the group is greatly injured. 
 
 The Sternum and Shoulder-girdle of the early stage in the swan (Plate L, 
 fig. 5), along with the wings, are remarkable for their small size at present. 
 There must be some ontological reason for this ; and putting together such 
 facts as are patent, an approximation to the truth of the matter may be made. 
 At present the sternum is entirely cartilaginous ; it remains so, and is very 
 small, relatively, in the large cygnets a month old. When it does ossify it 
 is by endostosis at first, and the three main tracts are imperfectly distinct 
 from each other. In fowls and struthious birds the sternum ossifies earlier 
 and by ectostosis, in very definite tracts ; though large-winged, the unwebbed 
 Palamedida3 have a smaller sternum than the Anatidaa ; but both groups 
 have sternum and wings large. The most generalized of the Anatidas are 
 the geese, and the true land geese most of all. The largest of all, by far, 
 the extinct Cnemiornis (Owen) of New Zealand,* and several existing forms, 
 are terrestrial birds: the most generalized forms I have met with, judging 
 from the structure of embryos at a similar stage as those of Cygnus nigricollis, 
 are Chloephaga poliocephala of the Falklands, and Cereopsis novce-hollandice of 
 Australia. 
 
 I therefore imagine the fore-parents of the Chenomorphae to have been 
 near akin to those of the Ratita? and those of the Gallinaceous tribes — all 
 land birds. In that case, after the dying out of the true teeth, those primor- 
 dial forms, neither geese, swans, nor ducks, at that time, acquired the webs 
 on their feet, and those horny succedunea to teeth that were needful for them 
 in their peculiar method of gaining a livelihood, namely by straining out 
 the mud of watery places for the sake of living food. Not the less did they 
 browse and. graze, as many of them do to this day; the most aquatic — the Fuli- 
 gulinse and the Merganserinae — being the most completely carnivorous. 
 
 The extension backwards of the sternum in birds — the "xiphoid" or 
 
 * This gigantic goose was fast becoming one of the Ilatitcc (Transactions, Zoological Society, 
 vol. ix., Plates XXXV. -XXXIX. ; and Cygnna falconeri was an Anserine swan (Transactions, 
 Zoological Society, vol. vi., Plate XXX.). 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 27 
 
 " metasternal " region* — is, in this embryo, only one-fourth as long as 
 the whole tract : the notch between each cartilaginous tract is further 
 forward than the insertion of the last sternal rib. The rostral jn'ocess, in 
 front, between the coracoid grooves, is small. The keel is rather acute- 
 angular in front, and dies out behind, not reaching to the end of the 
 median metasternal process. Only three-fourths of the costal edge has 
 sternal pieces ; these died out during development in the fore part : their 
 vertebral counterparts are seen above as the styloid ribs of the two last 
 cervical vertebrae. Seven cinctures are complete ; the eighth nearly so ; 
 the ninth is less than half developed ; and in two distinct tracts there was 
 an attempt to develop eleven cinctures. This makes one figure the ancestral 
 bird with a very long thorax. Yet in true land birds, and in the most archaic 
 in existence, more so truly than the Ratitae, the Tinamou only finishes 
 three cinctures (T. robustus ; T. variegatus has four), and it has the longest 
 sternum of any bird; it is almost all metasternum, and yet has a large keel.f 
 The coracoid grooves are separated by the small rounded "rostral process" 
 in the Anatidse: the coracoids (cr.), therefore, do not overlap as in many birds. 
 The falcate scapula (sc.) and the strong broad-based coracoid are quite normal, 
 and are ossifying fast : the " clavicular process," or precoracoid root, is small 
 in these types. The furcula (Plate IV., fr.), however, is the most instruc- 
 tive part of the shoulder-girdle, and makes most for a kinship between 
 these birds and the Ratitas. In the Tinamou the furcula is simple : it 
 has no cartilaginous nuclei ossified and fused, as in most birds, notably in 
 the Passeres, the Rapaces, and the Pelecaninae. In most of the Ratitae it 
 has died out; but styloid remnants — simple clavicles — are seen in Cassowary s 
 and Emus (" Shoulder-girdle and Sternum," Plate XVII., tigs. 3, 4). In 
 the Palamedidae the furcula is composed of two massive and simple clavicles 
 fused together as in Tinamou, and forming a U-shaped bone — quite like that 
 which has been made out in Archaeopteryx. The furcula of the swan is quite 
 similar, but not so massive nor so pneumatic as in Chauna chavaria. The 
 simple parosteal clavicles of Reptiles, because of their superficial, sub- 
 
 * See Lindsay : Proceedings, Zoological Society, 1885, pp. 684-716, Plates XLII.-XLV. 
 \ Transactions, Zoological Society, vol. v., Plates XXXIX. and XLI. 
 
 [4-] 
 
28 Cunningham Memoirs. 
 
 cutaneous nature, are more variable than the endo-skeletal part of the 
 shoulder-girdle : in Chameleons they are suppressed ; and in Crocodiles 
 only the third piece, the u interclavicle," is present (op. cit., Plate XL, 
 figs. 4 and 8). 
 
 Going back to an earlier stage, we see in the embryo duck (Anas boschas) 
 after nine days' incubation (Plate I., fig. 5) that the scapula and coracoid are 
 fused into one bar, which is bent upon itself at more than a right angle : it is 
 much less so in the adult. The early position is Reptilian, and so is the con- 
 tinuity of the two parts (see in the " Urodeles," op. cit., Plate III.). The 
 antero-inferior bar, or " pre-coracoid," has the same arrested development 
 as in the Rhea, Cassowary, and Emu (oj). cit., Plate XVII. ); and the mem- 
 brane that so strongly walls-in the interfurcular space has in it, above, a 
 small patch of nascent bone, the future " furcular ramus" (fr.). The 
 moieties of the cartilaginous sternum are uniting, and are sending down 
 a small keel; the costal edge has seven sternal pieces (s.r.), and there is 
 only room for one more on the pre-costal process — not two, as in the swan. 
 The hinder half of the metasternum is membranous at present. 
 
 The Wings of the Anatidce* 
 
 In the nearly ripe embryo of Cygnus nigrieollis the humerus and ulna 
 are of the same length ; the manus is one-eighth longer (Plate IV.). The 
 ends of the main rods are still unossified, as are the carpal segments; the 
 general form of each element is now the same as in the adult. 
 
 The proximal row of carpals has only the two normal avian pieces — the 
 radialef (Plate III., fig. 7), and the ulnare (ue.); the latter is evidently 
 morphologically compound, for it has two unequal lobes, one on the extensor 
 and the other on the flexor face of the limb. 
 
 The distal-carpals (d.c. 1 , (I.e. 2 , d.c. 3 ) are still distinguishable above the 
 metacarpals. The 1st (fig. 7, d.c, d.c. 1 ) is small and ventrally displaced ; it 
 lies below the larger lunate 2nd segment ; that piece is now fairly confluent 
 
 * For bibliographical notices, see "Fowl's Wings": Philosophical Transactions (1888), 
 pp. 385-398. 
 
 f The " radiale " carries a spur in Plectropterus (Sclater : "Ibis," vol. iv., 1886, fifth 
 series ; p. 300, fig. 3 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 29 
 
 with the 1st metacarpal (m.c. 1 ) in front; and the 3rd distalcarpal (d.c. 3 ) 
 behind. This latter is mainly on the ulnar side of the manus, for the 
 "index " and its carpal are inordinately large, and have dwarfed the parts 
 on each side; the large round head of the metacarpal of the index (m.c. 3 ) is 
 clearly seen wedged in between the 1st metacarpal (m.c. 1 ) and the 3rd 
 distalcarpal ((I.e. 21 ), and capped by its own large curved carpal (d.c 2 ). The 
 small patelliform 1st distalcarpal looks forwards and downwards towards its 
 own metacarpal (m.c. 1 ), which is only one-third the length of the next, and 
 is not yet ossified. This segment has a large proximal "trochanter," 
 partly formed of a band of fibro-cartilage ; this part, in some birds 
 (e. g. Parra and Pluvianus), and notably in the Palamedidse, carries a 
 defensive spur. The 1st metacarpal has hinged upon it a " pollex " (dg. 1 ), 
 nearly as large as the two last phalanges of the index (dg.' 2 ); of 
 course this latter has another — its proximal phalanx, and both are normal 
 digits as to the number of their segments. In each of these digits the 
 distal phalanx is the core of a claw. They are ungual phalanges ; they are 
 already ossifying at their tip, and the others have a shaft-bone. 
 
 But the proximal phalanx of the index has a flat dilatation on its hinder 
 or ulnar edge (dg. 2 ) ; and the metacarpal of the index has, in the duck, near 
 the top of its bony shaft on the ulnar side, a small accessory cartilage (Plate 
 I., fig. 6, m.c. 2 ) ; the dilatation on the proximal phalanx arises as a distinct car- 
 tilage later than the main segment. The 3rd digit has a metacarpal (m.c. 3 ) only 
 one-third the diameter of the 2nd ; it reaches only to the bony shaft of that rod 
 above ; but at its lower end it reaches a little further down ; its ends are still 
 soft, and the upper is modelled on the extensor face into a distinct head ; on 
 the flexor face it is confluent with its own distalcarpal (d.c. 2 ) This narrow 
 bar is bowed out in the middle so as to leave an interosseous space for the 
 muscle of that part ; below, it dilates a little, and then has articulated to it 
 a single phalanx (dg. 3 ), where in a Reptile there would he four phalanges ; this 
 is only one-third the size of the second phalanx of the index ; it is not yet 
 ossified. Altogether, the index has overshadowed and starved the 3rd or 
 hind-finger. As a rule, in old birds, this is the hindmost digit. There is, 
 however, a very small remnant of a 4th metacarpal on the flexor side of the 
 3rd near its top (Plate III., fig. 7 a , m.c. 4 ); the accessory cartilage attached to 
 
30 Cunningham Memoirs. 
 
 the 2nd metacarpal is on the extensor side. I shall refer to these parts 
 again in describing the Alcidre. 
 
 The wings, like the sternum of the cygnet (Plate V., fig. 7), grow 
 slowly ; all there is to remark upon, as yet, is the extension of the bony 
 shaft and the ossification of the 1st metacarpal (m.c. 1 ) 
 
 In old swans the relative, as well as the really great size of the wings, is 
 greatly altered from that of the nearly ripe embryo ; this is well seen by 
 comparing the fore and hind limbs. 
 
 In. that early stage the ulna was 17 millims long, and the tarso-tibia 27 
 millims. In the old white swan the ulna is 270 millims long, and the tarso- 
 tibia 203 millims, or only four-fifths. The humerus is now 287—5 millims 
 long, or 17 - 5 millims longer than the ulna. The manus is now 240 millims, 
 or 30 millims shorter than the ulna. But in the embryo the manus, as I 
 have shown, was one-eighth longer than the humerus and ulna, which were 
 both of the same length. 
 
 I found, in the old white swan, the distalphalanx of the pollex 10 
 millims long, and that of the index 14 millims ; they were, in both, straight 
 and sharp-pointed — they had lost their claw-form. Thus the specialization 
 in those birds is seen in the humerus becoming larger than the ulna, instead 
 of being the same size, while the manus. which was one-eighth longer than 
 both those segments, is now 30 millims shorter than the ulna, and 47*5 
 shorter than the humerus. The teleological bearing of this is, that the wings 
 have largely changed their size as compared to the legs ; they were only 
 half the size — they are now much larger. The overgrowth of the humerus, as 
 compared with the ulna, has reference to the quiet, buoyant, continued power 
 of flight in these birds ; the ulna has gained more room for the secondaries, 
 whilst the space for the primaries, although larger, is relatively less. The 
 humerus is the only pneumatic bone in the limbs of the Auatidae ; in Chauna 
 chavaria only the ungual phalanges retain the marrow. All these things 
 suggest that the Anatidee were, in their remote parents, stout strong-legged 
 land birds, with short wings, a small sternum, and with no special fitness for 
 an aquatic life, beyond that of wading in shallow waters.* 
 
 * Wolf's excellent figure of Chauna nigricollis (Proe. Zool. Soc, 1864, Plate XLL, p. 74) shows 
 that archaic hen-faced " Cheuomorph " in the very attitude anil act of wading ; its resemblance 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 31 
 
 If I were to go no further down, and no further afield, than this exami- 
 nation of the large embryo of the nestling and the old swan, half the interest 
 of the matter would be still untouched. I have still to describe the early 
 stages of the wing in the common cluck, and the rare conditions of this 
 part seen on the embryo of Chloephaga, and in the adult of one of the 
 Palainedidas. 
 
 Stage 1. — Wing of Embryo Duck (Anas boschas), 9th Day (less advanced). 
 
 The paddle-shaped fore-limb at this stage differs but little from the 
 hind-limb (Plate L, figs. 1, 2). There is a tendency to lobulation of the 
 spatulate end of the limb ; and this is manifestly due to the growth, along 
 certain lines, of radiating thickenings of the tissue which are fast growing 
 into pointed hyaline cartilages. There are, already visible, three such 
 rays in the fore-limb, and four in the hind-limb. There is, indeed, an 
 arrest, almost suppression, of two of the normal rays in the wing, and of 
 one in the leg. 
 
 If these limbs be considered to be the modifications of what we see 
 everywhere in Reptiles, it is evident that some of the rays have been 
 smothered in their growth — probably, in some degree, by the great start 
 that the developed parts have got. 
 
 Potentially, the seeds, so to speak, of the missing rays were duly sown ; 
 for in the case of the wing, one of the two lost rays makes a little attempt 
 at growth, and the one missing ray in the leg does the same; but the 
 developed parts have " sucked their verdure out." 
 
 Already, the main regions of the limb are differentiated ; and the chief 
 segments have become hyaline cartilage ; the more inconspicuous elements 
 and distal parts of the skeleton of the wing are still composed of embryonic 
 cartilage or "indifferent tissue"; as to the larger rods, I have not 
 overdrawn their distinctness. Whilst the muscles are still in formation, 
 the harder tracts of tissue for their origin and insertion are already 
 prepared. This is well seen in the humerus (Plate L, fig. 1, outside view of 
 
 to the coots (Rallidse), in respect of its huge toes, which are really those of a swan without 
 the web, made the old Ornithologists (Vigors, Cuvier, &c.) put it with the Eallida; and also along 
 with Parra and Megapodius. 
 
32 Cunningham Memoirs. 
 
 right wing) and in the cubitus (r.,u. ). Distinct from these parts, but only semi- 
 distinct from each other, are the parts that form the carpus ; on the ulnar side, 
 a large wedge of soft cartilage (ue.) is seen, with its sharp edge above ; and 
 on the radial side there is a thick mass (re.) notched both by the ulna (u.) 
 and the radius (;■.) Beyond these, at the mid line, another large mass is 
 seen (d.c. 2 ), and on its ulnar side a much smaller half-distinct nucleus (d.e. 3 ); 
 these both become the second and third distalcarpals. Growing forward from 
 them, quite cartilaginous rods are seen ; these, which are more and more 
 soft towards the end, are distinctly segmented a little beyond their middle. 
 Thus we have the large second and the small third metacarpals (m.c. 2 , m.c. 3 ), 
 with their sprouting phalanges (dg.", dg. 3 ) forming the second and third digits. 
 The first distal carpal is not evident in this stage (I shall show it in the 
 next) ; but the first metacarpal with its sprouting digit, the pollex, is already 
 clearly seen. 
 
 The small rough model of a bird's-wing skeleton is to be clearly seen in 
 this weak rudiment up to the wrist (carpus) ; but the three rays are the 
 diverging, sprawling fingers of a Reptile. 
 
 Stage 2. — Embryo of Duck after Nine Dags' 1 Incubation [more advanced). 
 
 In a further growth of the wing (Plate I., fig. 3, inside view of right 
 wing) the sprawling of the fingers is not so great, and the softer parts are 
 more clearly outlined ; they are now almost hyaline cartilage. The pre- 
 paration here figured was a stronger and larger embryo than Stage 1, but 
 the period of incubation was the same. The elbow is now definitely bent ; 
 and, the whole structure becoming avian, the bird is becoming more and 
 more, the reptile less and less. 
 
 What may be called the necessary and normal parts of the skeleton of the 
 wing are all now present. These are the parts chosen beforehand by the 
 elective affinities of the morphological force to form this — the strangest 
 type of limb. The human arm and hand are simple and primitive, and 
 nearly normal in comparison with this "freak," which is specialized for 
 flying. We have only to look at the large masses of hardening cartilage 
 that form the avian radiale and ulnare {re., ue.) to see that they are only semi- 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 33 
 
 differentiated lumps of tissue. They, as can be proved by their behaviour 
 in certain birds, represent two or sometimes three carpals of more normal 
 fore-limbs ; the ulnare is in two lobes even now. 
 
 The three distalcarpals (fig. 3, d.c. 1 , d.c. 2 , d.c. 1 ) can all now be seen on the 
 inner or flexor side of the wing; the first (d.c. 1 ) is a small hemispherical 
 nucleus inside the junction of the second metacarpal witli it distal carpal 
 (m.c. 2 , d.c. 2 ). The latter is a large lunate mass, curving round the head of its 
 own metacarpal ; it thrusts the third distalcarpal (d.c. 3 ) forward. This is 
 an oval piece, larger than the ventrally displaced first, but oidy one-fourth 
 the size of the second. 
 
 The pollex (dg. 1 ) shows its distal phalanx as a conical mass of soft tissue 
 on the end of the proximal phalanx. The index (dg. ") and the third digit (dg. 3 ) 
 have only their proximal phalanges in the state of hyaline cartilage. The 
 third digit is drawing nearer to the second, which all along has been twice 
 its bulk, but not much longer. 
 
 Stage 3. — Embryo of Duck, after Twelve Days' Incubation. 
 
 During the next three days the transformation of the tridigitate paw 
 (or paddle) into the wing has been very rapid, and almost complete as to 
 form. 
 
 The main bones (Plate I., fig. 6, r., u.) have acquired an ectosteal 
 sheath, and all the elements are well solidified as hyaline cartilage : more- 
 over, fusion of some of them has already taken place, and new parts have 
 become differentiated. The various joints, or condyloid faces of the 
 segments, are now fairly modelled by the process of mutual adaptive 
 growth of contiguous parts : these are very perfect, notwithstanding the 
 limited mobility of this metamorphosed member. The proximal carpals, 
 the radiale and ulnare (Plate I., figs. 6, 7, re., ue.), are now very perfectly pre- 
 formed in cartilage : the radiale is a massive lunate wedge ; the ulnare is a 
 bilobate segment, with its " elbow" behind, and its longer oval lobe on the 
 inside : it overlaps both the ulna and the third distalcarpal (u., d.c. 3 ). 
 
 The large projecting second distalcarpal (d.c. 2 ) is now confluent with 
 the first metacarpal (m.c. 1 ) in front, and the third distalcarpal (d.c. 3 ) 
 
 KOYAL IEISH ACADEMY CUNNINGHAM MEMOIRS, NO. VI. L^J 
 
34 Cunningham Memoirs. 
 
 behind : thus, its own huge metacarpal (m.b. % ) has its head inclosed in a 
 thick cap of cartilage. Its outline, however, is quite clear ; so also is that 
 of the third metacarpal (m.c. 3 ) ; but its distalcarpal (d.c. 3 ) is fused above. 
 The first distalcarpal (fig. 7, d.c. 1 ) is now a clear bud of cartilage, flattened on 
 its adherent face, and placed inside the head of the second metacarpal. The 
 first metacarpal (m.c. 1 ) runs parallel with the unossified head of the second ; 
 it is half the size of that head, and has a large flat " trochanter" on its 
 proximal end ; it then narrows and forms a condyle for the pollex (dff. 1 ). 
 That digit, with its metacarpal, is half the length of the whole index, meta- 
 carpal, and phalanges, together ; but its proximal phalanx is as long, but 
 not as stout, as that of the second; its distal phalanx (so-called ungual) is 
 almost the size of that of the index, which is nearly as large as the 
 second or middle joint of the digit. In the pollex, especially, it is seen that 
 the distal phalanges are not ungual as yet, but are lobate and flat at their 
 free end, and represent not the claw- joint of a Reptile, but the last piece in 
 the soft-ended finger of an amphibian. 
 
 At present, the terminal pieces of all the three digits are alike ; but that 
 on the third (dg. 3 ) represents merely the proximal stump of a Lizard's third 
 fore-toe, which has four phalanges in it. The first and second digits in this 
 wing are normal ; the third is aborted. 
 
 But a much more abortively- developed digit is seen behind the third : 
 this {in.c. i ) is a rudiment (or remnant) of the fourth metacarpal of a Lizard's 
 fore-foot : it is on the flexor side of the hind margin of the third, close to 
 its rounded and distinct top. This remnant is common in the Carinatse : 
 in Opisthocomus this digit re-appears as a proximal phalanx ; it is, in that 
 bird, a distal, not a proximal, remnant. 
 
 An accessory cartilage is now seen as a thin flap on the ulnar side of the 
 proximal phalanx of the second digit (dg.~): the second and third meta- 
 carpals have acquired a considerable bony (ectosteal) tract. The distal 
 phalanx of the second digit is not so well developed on the right (fig. 6«) 
 as on the left side : bilateral asymmetry is not uncommon in the wings 
 of birds. 
 
Me. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 35 
 
 Stage 4.— fflmbryo of Duck, after Fourteen Days' Incubation. 
 
 After two days more there are two new ectosteal tracts — those of the 
 proximal joint of the pollex and of the index (Plate I., fig. 8, dg. 1 , dg. 2 ) ; the 
 other parts are similar, but larger: the first distal carpal (d;c l ) is growing 
 towards its own metacarpal (m.c. 1 ). The difference in the size of the two 
 lobes of the ulnare is now well seen (figs. 8, 9, tie.). The distal phalanges of 
 the pollex and index (dg. 1 , dg. 2 ) are becoming curved as ungual joints. 
 
 Stage 5. — Embryo of Duck, after Eighteen Days' Incubation. 
 
 In this stage (Plate II., figs. 4—6) there are several points to be noticed. 
 The second phalanx of the index (dg. 2 ) is ossifying; and the large curved distal 
 joints of both that and the first digit (dg. 1 , dg. 2 ) have a terminal horny sheath. 
 In the more enlarged figures (figs. 5, 6) there are some important parts 
 displayed more plainly : the accessory tract of the second metacarpal (m.c. 2 ), 
 which is very small in the Anatidse, and very large in the fowl tribe, can be 
 seen as a narrow tract of cartilage growing forwards from the ulnar side of 
 the great distalcarpal (d.c. 2 ). The first distalcarpal (fig. 5, d.c. 1 ) is now a 
 thick band of cartilage which has grown across the head of the second 
 metacarpal, and has applied itself to its own metacarpal (m.c. 1 ). In the same 
 view the fourth metacarpal (m.c. i ) is plainly seen as a small pyriform nucleus 
 of hyaline cartilage. On the outer or extensor face (fig. 6) the peculiar 
 free end of the outside of the third metacarpal is also well seen. 
 
 Stage 6. — Embryo of Duck, just Ripe. 
 
 In this stage I have shown the proximal end of the manus (Plate II., 
 figs. 8, 9) : it differs but little from the last ; but the fourth metacarpal (m.c}) 
 is becoming confluent with the top of the third (m.c. 3 ) 
 
 Stage 7. — Duckling Three Days Old. 
 
 The same parts are shown in this stage (Plate II., figs. 10, 11): the 
 fourth metacarpal (m.c. 4 ) is now confluent with the third (m.c. 3 ) : the accessory 
 
 [5*] 
 
36 Cunningham Memoirs. 
 
 part to the second metacarpal (m.c. 2 ) is now a thin point of cartilage 
 embracing the large bar on its ulnar edge above. 
 
 Stage 8. — Old Duck (Anas boschas). 
 
 As compared with that of the swan, the wing of the mallard — and also 
 that of the tame duck and of the sub-family Anatidae generally — is 
 relatively, as well as really, short : they are heavy birds to be carried with 
 such wings as they possess. 
 
 In these smaller forms the cubitus is considerably the smallest of the 
 three divisions of the wing-skeleton, and the manusthe longest ; they beat 
 their wings rapidly in flight, unlike the " longipennes," birds with very 
 long humeri. During the growth of the duckling, the carpals all acquire an 
 endosteal centre ; the two proximal segments remain free ; the three distal 
 become fused with the metacarpals, and these with each other ; the second 
 and third at both ends. The ungual phalanges of the pollex and index 
 remain in the adult as sharp and straight pieces: the latter is the longer; 
 and thus, besides the free synovial articulations of the two proximal carpals 
 with the cubital bones above, and the compound manus below, the pollex 
 has two, the index three, and the third digit one, moveable articulation 
 permanent — just as much as is necessary in this transformed arm and hand, 
 with its marvellous investment and its new function. 
 
 The Hip-girdle of Anas boschas. 
 
 In this species I am able to give three stages earlier than that of the 
 nearly ripe embryo of the swan (Plates IV. and V.); and these show what 
 transformation an average reptilian pelvis undergoes in the bird, correla- 
 tively with that of the shoulder-girdle and wing. The changes are very 
 great in these parts, but not so great as in those. 
 
 Morphologically, the steps or stages of this metamorphic process may be 
 said to be four in number: we have — 1, the general Reptilian; 2, the 
 Ornithoscelidau ; 3, the Struthious ; and 4, the normal Carinate stage. 
 These stages are not so clearly defined in the hind-limbs : they are very 
 marked in the moieties of the hip-girdle. 
 
Me. W. K. Pakker. — Morphology of the Duck and the Auk Tribes. 37 
 
 Stage 1. — Pelvis of Embryo Duck, Nine Days' Incubation {less advanced). 
 
 This first, or Reptilian, stage of the hip-plate (Plate II., fig. 1) is shown 
 in relation to the hinder-part of the vertebral chain, which is rapidly form- 
 ing round the notochord (nc), and over the myelon. 
 
 This stage is well illustrated in Miss A. Johnson's valuable Paper on the 
 development of these parts in the Chick.* The vertebral formula of the 
 adult duck is as follows : — 
 
 C. 16; D. 5; D. S. 3; L. S. 3 ; S. 3 ; U. S. 7 ; 
 Cd. 8 + 5 = 13 : Total, 50. 
 
 Of these the last two cervicals have free ribs : and also the first three 
 sacrals, or dorso-sacrals ; and there are rib-bars on two or three — originally 
 on five — of the urosacrals. 
 
 Now, the three true sacrals are exactly over and between the acetabula. 
 In this first stage, therefore (Plate II., fig. 1), there are four in front of 
 these covered by the anterior lobe of the ilium (pre-tlium), and three uro- 
 sacrals by the posterior lobe or post-ilium — ten altogether, instead of sixteen 
 as in the adult. At a still earlier stage there would be fewer, f in which stage 
 the crest of the ilium is scarcely more dilated than the " supra-scapula," as in 
 some Lizards (see, in Stellio, Shoulder-girdle and Sternum, Plate XL, fig. 1, 
 s.sc). It has, moreover, to be kept in mind that hosts of small and nobler 
 birds have only ten vertebras embraced by the ilia, although eleven is the 
 most common number : the duck is a medium, the swan an extreme, case. 
 
 In Ignanodon bernissartensis there are ten vertebras fairly between the 
 ilia, as in my first stage in the embryo duck. J This first stage, however, 
 has the hip-plate, as a whole, not in an Ornithoscelidan, but in a general 
 Reptilian condition. It is instructive to see how the pre-ilium at present 
 preponderates over the post-ilium ; for it is the great development of the 
 latter region that makes the bird's pelvis so remarkable; a still more 
 remarkable fact being the adumbration, by the unwieldy Iguanodon, of the 
 
 * Studies, Morph. Lab., Camb., vol. ii., Plate IV., figs. 3-6. 
 
 f See A. Johnson, op. cit., Plate IV., figs. 3, 4. 
 
 X Dollo, Bull. Mus. Koy. Hist. Nat. Belg., t. ii., Plate V. 
 
38 Cunningham Memoirs. 
 
 hip and legs of such small, light, airy forms as the nobler types of birds. 
 Of the vertebrae that are built in between the hip-plates the last seven are, 
 properly speaking, caudal ; then follow, as a rule in this bird, thirteen 
 more, the last five forming the uropygial piece. But I have seen as many 
 as ten segments in that terminal region (Plate II., fig. 12); that would give 
 twenty-five for the post-sacral or caudal series.* These, were they elongated 
 as in the tail of Archseopteryx, would have formed another " Saururous" 
 type. It is easy to imagine such a hind-spine as the one depicted (Plate II., 
 fig. 1) as rapidly developing into the tail of a Saururous bird, instead of 
 contracting itself into the stunted and largely fused uro-sacral and caudal 
 series of a duck, or of any normal Carinate bird. 
 
 Palaeontology is extremely tantalizing at this point. Geologically not 
 so much older than Marsh's toothed birds, the Archaeopteryx has no claim 
 of fatherhood upon them : the gulf is not so great as between the 
 Iguanodon and the Humming Bird ; it is, however, unbridgeable, notwith- 
 standing. 
 
 One more remark. In cartilaginous fishes — above all, in the Ray 
 family — the neck becomes a quasi-s&cram ; for the shoulder-girdle is fixed 
 like the hips of higher forms : the fore limbs dominate the hind limbs, as 
 they are the chief paired organs of progression. 
 
 The flying bird would seem to be relapsing in this respect, the fore 
 limbs being its main organs of progression : but the bird is merely a land 
 animal modified ; hence its hind limbs are well developed also. 
 
 In the formation of these noble feathered forms it is instructive to see 
 the part played by the notochord, and the rapid manner in which it becomes 
 contracted and obscured, and then transformed into a mere ligament ; in my 
 first stage (Plate II., fig. 1), had it gone on growing and developing t'he 
 vertebral segments on and around it, this bird must have soon become 
 one of Professor Huxley's " Saururae " ; it was, however, ordained to become 
 one of his Carinatce. 
 
 By careful dissection of early embryos, Miss B. Lindsayf was able to 
 
 * See Proceedings, Zoological Society, 1863, p. 1-8. 
 f Proceedings, Zoological Society, 1885, p. 704. 
 
Mr. W. H. Parker. — Morphology of the Duck and the Auk Tribes. 39 
 
 show that the shoulder-girdle of the bird arises as three {apparently") separate 
 tracts of embryonic cartilage ; that is, however, prior to the formation of 
 true or hyaline cartilage, for this tissue runs freely from the scapular to the 
 coracoid region, thus forming one curved bar. The jDre-coracoid tract only 
 partially ossifies, and that in two ways, namely, by a rudiment grow- 
 ing directly from the coracoid, and often by one or two distinct cartilaginous 
 tracts; the rest of the anteroinferior bar grows into a mere "parostosis" — 
 the simple clavicle. But there is no parostosis in the hip-girdle : the whole 
 structure answers to such a shoulder-girdle as that of the Amphibia, Chelonia, 
 and of Struthio camelus. (See " Shoulder-girdle and Sternum, Plates III. — 
 VIII. ; Plate XII. ; and Plate XVII., figs. 5, 6.) This subject is rendered 
 difficult through the peculiar development of the hip-plate in the Dinosaurs. 
 (See Dollo, op. cit., Plates III. and V. See especially Plate III., fig. 2. 
 In Iguanodon bernissartensis the pubis sends forwards a large broad prepubic 
 bar, called by Dollo "pubis"; whilst the already rotated pubis — the long, 
 narrow hind-part — he calls "post-pubis"; the term pre-pubis is the better 
 for the fore-part. The ischium also, where it binds upon the post-pubis, 
 sends down upon that bar a shorter anterior and a longer posterior process, 
 to enclose the proper obturator foramen. Now, if these parts and pro 
 cesses be compared with those seen in the shoulder-girdle of certain Lizards, 
 e.g. Iguana tubcrculata {op. cit., Plate IX., figs. 1, 2), and if the unossified 
 free edge is supposed to be absent, then we are shown how that these plates 
 may send out secondary bars : in the Iguana there is one large bar from the 
 scapula, and two in front of the coracoid proper. So I interpret the pro- 
 cesses on the pubis and ischium of the Dinosaurs. In birds the pre-pubis 
 is often suppressed, but it has a considerable development in the Ratitse, 
 Tinamidas, Gallinacese, and the Ground Cuckoos (e.g. Geococcygx, &c). In 
 Dollo's Plate III. the pelvis of a young fowl is figured : in it the small pre- 
 pubis is shown to be ossified by the ilium, and not by the pubis. In other 
 Carinatse, as far as I have seen, the same thing takes place ; a good instance 
 at hand being the pelvis of a newly-hatched quail (Coturnix dactylisonans). 
 In it the pubic ossification reaches the base of the finger-shaped pre-pubic 
 lobe ; afterwards the suture between that bone and the ilium runs directly 
 inwards, as in Dollo's figure; and thus the spur receives its bony deposit 
 
40 Cunningham Memoirs. 
 
 from the ilium. In an earlier stage of Phasianns versicolor the spur is 
 endosteally ossified, and is in front of the suture between the ilium and 
 pubis.* 
 
 I feel certain that Professor H. G. Seeley, F.R.S.,t has unnecessarily 
 raised a difficulty and a doubt about the pubis of the Crocodile ; and that the 
 view taken by Ratlike, Hoffman (in his later writings), Huxley, Hulke, and 
 myself, is quite right ; our interpretation of this part will be found to be 
 true. In perfect harmony with these received views are the figures given 
 in Miss A. Johnson's Paper {op. cit., Plate IV., figs. 3—6) ; and my own first 
 stage in the duckling, fig. 1 (Plate II.), as compared with figs. 2 and 3, 
 suggest the same identification, exactly. J 
 
 In my figure of the first and second stages in the embryo duck I have 
 shown a considerable amount of distinction between the three main parts. 
 This is seen still better in a chick than in these embryos. In it, espe- 
 cially when the pubis and ischium have just rotated, the three parts are 
 semi-segmented from one another ; a deepish chink is formed, as although 
 a piece of cardboard were nearly cut through with a knife ; the chinks are 
 filled with connective tissue cells : at the first adjustment with a high power 
 these seem to pass through. A deeper adjustment shows an extremely thin 
 tract of cartilage on the inner face of the object: anyhow, this is very 
 noteworthy, showing that the root and foundation of the limb is formed of 
 three rays — parts that are homologous with those that form the fore-limb. 
 
 * In a letter from one of the best of living paloeontologists, J. "W. Hulke, Esq., F.K.S., received 
 December 15th, 1887, in answer to one from me, he says : — " In your fig. 3 of a bird's pelvis 
 you represent the pre-pubic spur as wholly iliac. The corresponding spur in Apteryx, and in 
 alien ainericana certainly contains a pubic element ; for its suture, in immature specimens, runs 
 through the spur, which has thus an iliac and a pubic component." 
 
 Bearing thereon, Mivart's figure of the pelvis of a young Ostrich (Trans., Zoological Society, 
 vol. viii., p. 437, fig. 74) shows this; but unfortunately the cartilaginous spur was not pre- 
 served nor figured. Yet, if that figure be compared with one of the adult (p. 433, fig. 71), it 
 will be evident that the ilium and pubis meet in the root of the process. 
 
 f Proceedings, Royal Society, 1887, pp. 235-242. 
 
 J The embryos of the Crocodile referred to by Professor Seeley as coming from me {op. cit., p. 
 24) were unfortunately too old for such researches. Two years afterwards I recovered the 
 early stages which I had wished to put into Professor Seeley's hands. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 41 
 
 The flabelliform ilium (il.) is parallel with the spine in its dilated part ; 
 but its axis is at a right angle with it : such an ideal line would pass 
 directly between the two lesser bars, the pubis and the ischium. The former 
 of these has now very nearly the position which is permanent in the 
 crocodile.* 
 
 In this early stage the pubis and ischium diverge at less than a right 
 angle : they are broad and flattish tracts composed of hyaline cartilage in 
 their upper three-fourths, but are still in a state of " indifferent tissue " 
 below : the angles of the ilium are in the same stage, as yet. The deep 
 setting of the femur has stopped the growth of the cartilage, so as to show, 
 already, a large hole in the fundus of the acetabulum. 
 
 Stage 2. — Pelvis of Embryo Duck of Nine Days' 1 Incubation {more 
 
 advanced). 
 
 In this stage the hip-girdle embraces fifteen of the general sacral series 
 of vertebrae ; only the last appears like a pre-caudal. In a general way 
 this condition is very Dinosaurian, for the pubis (pb.) and ischium (isc.) are 
 rotated backwards, but are still at a great distance from the caudal spine, 
 and are relatively very large. Afterwards (fig. 3) the pubis becomes much 
 longer than the ischium ; now it is but a little longer : in Dinosauria, as a 
 rule, the ischium is much longer than the pubis. There is no pre-pubic 
 spur ; and, at present, besides the absence of any bony deposit, the distal 
 parts of all the three bars are still composed of indifferent tissue. They 
 are all free from each other behind, so that there are no "fenestra?," but 
 a series of long notches, a sacro-iliac, an ilio-ischiatic, and an obturator 
 notch. A comparison of this, of the next stage, and of that of the almost 
 ripe embryo of the swan, with those of the adult Ratitse and of the Gallo- 
 struthious Tinamous, is very instructive as helping to throw light upon the 
 forms that birds assumed in the olden times. 
 
 We have, however, to be very careful to sift out the specialization of 
 
 * Huxley, Proceedings, Geological Society, 1869, p. 27, fig. 3; Dollo, op. cit., Plate III., 
 fig. 1 c. 
 
 ROYAL IRISH ACADEMY CUNNINGHAM MEMOIRS, NO. VI. [6] 
 
42 Cunningham Memoirs. 
 
 arrested types ; for, as a rule, existing archaic forms are in some respects 
 more modified than the culminating types ; and we must recollect that they 
 have as long a list of ancestors, and have been as long in existence in the 
 loins of those ancestors, as the newest and noblest forms. 
 
 That the Ratitas represent several distinct families of birds there 
 can be no doubt ; nor can it be doubted that the Tinamous are less 
 degraded archaic forms closely allied to them. I have already shown how 
 near the embryo swan's pelvis comes to that of the African ostrich. In 
 this second stage of the duck the hip-plate wants but little further growth 
 and modification to make it into one like that of the cassowary.* In a few 
 birds [e.g. the Buceridas and Pieidse) the pubis, in the adult, becomes 
 fused with the ischium, below, as the post-ilium does normally, above. In 
 the cassowary all these bars are fused together in the cartilaginous condi- 
 tion: a little further chondrification would have done this in this second 
 stage of the duckling. Further, in the chick, at this stage, the pelvic plate 
 is precisely like that which is seen in the adult Tinamou. All these things 
 are to be noticed and kept in mind.f 
 
 Behind the sixteen vertebras that are, all but one, enclosed between the 
 hip-plates there are thirteen segments, forming the caudal series : these are 
 terminated by the blunt end of the notochord (no.). 
 
 The rapidity of this pre-natal transformation is extremely great — as 
 great as anything to be seen in the flowering of plants. The first and second 
 stages had both been incubated nine days ; but the second had got, in some 
 way or other, a fair day's start, as to growth, of the first ; and, in this 
 short time, the whole difference between a general Reptilian and a Dino- 
 saurian pelvis had been effected. 
 
 Stage 3. — Embryo of Duck after Tioclvc Days' Incubation. 
 
 Here (Plate II., fig. 3), we see how rapidly the Carinate bird's pelvis 
 passes into its typical condition : the general size has greatly increased ; 
 
 * Philosophical Transactions, 1888, B., Plate LXV., figs. 8-10. 
 
 f See Mivart, Transactions, Zoological Society, vol. viii., pp. 385-451 ; and vol. x., pp. 1-52 ; 
 and " Gallinaceous Birds and Tinamous" : Transactions, Zoological Society, vol. v., pp. 149-241, 
 Plates XXX1Y-XLII. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 43 
 
 the cartilage is completed, and in parts is being transformed into bone. 
 The pre-ilium (pr.i.) is now broader and relatively shorter; and the post- 
 ilium (pt.i.) is well ossified, and is very broad behind the sacro-ischiatic 
 fenestra (s.i.fX That space is not yet enclosed by fusion of the post-ilium 
 with the ischium (isc.), but lies upon its hinder half, or nearly half; its 
 broad, lobate hind-part lies upon the long, curved, and spatulate hind-part 
 of the pubis {pi.). As in the African ostrich and the swan, the pubis of 
 the duck and its congeners becomes greatly unlike that of a Dinosaur : 
 instead of being shorter it is one- third longer than the ischium. Bony 
 deposit is seen both in the pre-ilium and the post-ilium, fore and aft of the 
 acetabulum (ac. ), and at the lower border : the bony shafts of the pubis and 
 ischium are rapidly elongating ; that of the former remains unossified at its 
 dilated end in the adult, and then the pubis is twice as long as the ischium : 
 it is somewhat shorter in Stage 1, a little longer in Stage 2, and one- 
 third longer in Stage 3. These pubic bars differ little in the ostrich and 
 the duck tribe, except that in the latter they do not coalesce, but remain as 
 distinct elastic supports to the oviduct in oviposition. 
 
 The Hind-limbs* of Anas boschas. 
 
 Stages 1 and 2. — Embryo of Duck, Nine Days' Incubation (less, and more 
 
 matured). 
 
 My earliest stage (Plate I. , fig. 2) is very nearly the equivalent of that 
 given by Miss A. Johnson in the chick (op. cit. Plate V. fig. 9). It is 
 remarkably like the fore limb (fig. 1) of the same stage, already described; 
 but it has four developed digits, and the rudiment of a fifth. 
 
 The main rods are composed of hyaline cartilage, sharply differentiated 
 from the surrounding tissue: the distal parts are still "indifferent" and 
 soft. The rapidity of growth of these embryos is well illustrated by a 
 comparison of the humerus with the femur (fig. 1, h; fig. 2,/.); for they 
 have already acquired their peculiar form. In the next segment, the leg, 
 
 * The reader is referred to the following Papers out of many on the subject. They will be 
 sufficient to show that it has taken a quarter of a century to find out what are the real elements 
 
 [6*] 
 
44: Cunningham Memoirs. 
 
 the two limbs are now sharply in contrast ; for the fibula (fig. 2, fb.) is only 
 half as thick as the radius (fig. 1, r.) ; moreover, the inner (or pre-axial) rod 
 in the wing is the shorter and slenderer piece : in the leg it is the outer (or 
 post-axial), namely, the fibula (fig. 2, fb.). This difference and the oppo- 
 site direction in which the limb is bent — the elbow backwards, and the knee 
 forwards — show what great changes the ancestral amphibian limb has under- 
 gone.* 
 
 The pala3ontologist will see at once how carefully the bird walks in the 
 steps of the Dinosaurs. My figure of the skeleton of the leg (fig. 2) can be 
 simply superimposed upon his. There is part for part, digit for digit : the 
 nearly useless fibula, dominated by the one necessary segment of the leg 
 proper, the tibia, is already slender and short ; it is only one-third the thick- 
 ness of the tibia, and its terminal part runs short of the ankle-joint: it is 
 only five-sixths of its proper length ; whilst the distal part of the tibia is 
 dilated so as almost to reach the fibular, or outer, edge of the limb. What 
 seems like an " elbow " at the top of the tibia is, in reality, the rudiment of 
 the large, folded cnemial crest: this part is developed like a "trochanter," 
 and always has its own epiphysis in a young bird. In many birds there is 
 no other epiphysis whatever. 
 
 of this remarkably modified limb — a limb curiously transformed from what is typical, and, what 
 ■was still more unexpected, its almost perfect conformity with that of the Dinosaurs. 
 
 W. K. P.: "Osteology of Balceniceps rex": Transactions, Zoological Society, vol. iv., 
 1851-61, p. 343. 
 
 Gegenbaur, C. : " Vergleichend-anatomische Benierkungen iiber das Fussskelet der Yogel" : 
 Archiv. fiirAnat. und Phys. Jalirgang, 1863: pp. 450-472. 
 
 Huxley, T. H. : " Dinosauria and Birds." — Proceedings, Geological Society, 1869, pp. 12-31. 
 
 Morse, E. S. : "On the Identity of the Process of the Astragalus with the Intermedium." — 
 Anniversary Memoirs, Post. Soc. Nat. Hist,, 1880, Plate I., pp. 1-10. 
 
 Baur, G. : "Her Tarsus der Yogel und Dinosaurier."— Morph. Jahrbuch, Bd. VIII. (Taf. 19, 
 20, pp. 417-456. 
 
 Johnson, A. : " On the Development of the Pelvic Girdle and Skeleton of the Hind-limb in 
 the Chick."— Stud. Morphl. Lab. Camb., vol. ii., 1886, Plates IV., V., pp. 13-27. 
 
 W. K. P. : Proe. Hoy. Soc. 1887, pp. 57-58 : N.B.— On p. 58, line 11 from the bottom, for 
 " always," read " never." 
 
 * This is not well shown in the somewhat diagrammatic figures here given, in which the inner 
 or anterior side is figured behind and below. 
 
Me. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 45 
 
 But in all birds, whilst growing, there is what seems to be a large distal 
 epiphysis to the tibia.* 
 
 The absence of any apparent tarsal bone in existing birds has been so 
 long taken as a fact about which there is no question, that, even now, some 
 of my fellow-labourers are still sternly opposed to such a great primary 
 complexity in this part, as for some years past I have been able to demon- 
 strate. 
 
 Both in Dr. G. Baur's figures of sectionsf and in the figure, just referred 
 to, of Miss A. Johnson there is no sign of a cartilaginous intermedium, such 
 as I have figured in my first and second stages (Plate I., figs. 2 and 4, /.). 
 Happily, however, they both show the distinctness of the tibiale and fibulare, 
 and also the proximal rudiment of the fifth metatarsal. My preparations 
 of these parts in the duck's embryo were made in the early part of 1887: 
 those of the chick in a stage equal to that of Miss Johnson's fig. 9 were 
 made a year before. After lying in oil of cloves for some months all these 
 preparations were mounted in Canada balsam : they show still more clearly 
 now what I discovered then. In Dr. Baur's method — by sections — nothing 
 would be easier than to miss the thin intermedium ; for it lies above and con- 
 siderably in front o/the tibiale and fibulare. Both under a lower and a higher 
 power it can be clearly seen as a thin pyriform cartilage, with its broad 
 end below, and lying in front of the fibrous lower end of the fibula (fb.). 
 The tibia (fig. 4, t.) soon gets behind it, as it becomes very much dilated 
 below. 
 
 When the microscope is adjusted so as to show the tibia, fibula, tibiale, 
 and fibulare (Miss A. Johnson's fig. 9 shows this well), then there is no 
 intermedium to be seen. The gentlest elevation of the object glass, how- 
 ever, makes all these jjarts cloudy. And now the intermedium comes clearly 
 into view : it may easily be mistaken, even then, for a part of the dilated 
 base of the tibia. Now, as this distinct tract of cartilage becomes ossified 
 by ectostosis at about the middle of incubation ; and, as the tibiale and 
 
 * My figures of this pseudo-epiphysis in an emu chick, six weeks old, were made in the year 
 1842. After much meditation upon this anomalous structure, I, at length, timidly suggested that 
 this part was, in reality, the astragalus, and not an epiphysis, 
 
 f " Der Tarsus der Vogel und Dinosaurier," Plate XX. 
 
■JL6 Cunningham Memoirs, 
 
 fibulare are still mere endosteal nuclei in the centres of the cartilage in cygnets 
 one month old, how can the ascending process be a mere outgrowth, or peri- 
 osteal addition, to either the tibiale or fibulare, or both parts, which have no 
 such periosteal structure possible until the bird is fairly adult? Also, to 
 which of these tarsals does it belong? and why do they develop this tibial 
 clamp, seeing that they must so soon be fused with the main bone ? 
 
 Another question arises, namely, is it a tarsal bone ? — was it not a third 
 shaft-lone in the leg of the old ancestors of the reptiles and birds ? As 
 cartilage, it arises earlier than the tibiale and fibulare — as bone, much 
 earlier ; and its mode of ossification is not that of any. tarsal (or carpal) 
 that I know of.* 
 
 At present the fibulare (fie.) is a round nucleus of soft cartilage, only 
 one-third as large as the transversely-expanded tibiale (te.). This is well 
 shown in the chick in Baur's sections, and in Miss A. Johnson's dis- 
 section. 
 
 The distal part of the tarsus is in a very undifferentiated condition. 
 Only one nucleus can be traced (d.t.): this appears over the middle of the 
 perfect metatarsals (m. t. 3 ) ; it then grows right and left as a horizontal 
 wedge. The most evident subdivision of this piece is to be seen in nestling 
 sparrows (Passer domesticus) when the bony deposit is in these lobes. 
 Belonging to the 2nd, 3rd, and 4th metacarpal, this piece corresponds with 
 the inner part of the "cuboid," and the outer and middle "cuneiform" 
 bones of one foot. But in our foot there is an element called the 
 " scaphoid " : it is wedged in between the astragalus (tibiale) and the three 
 cuneiform bones. This element is more or less developed, generally, in 
 embryo birds : in fowls, struthious birds, and Tinamous, and in arboreal 
 birds generally, it becomes ossified, and serves as a sesamoid to the 
 plantar tendons. Morse (op. cif., Plate I., fig. 8) figures it in the embryo 
 of the Eider duck, and puts a ? to it. 
 
 It is not quite distinct even in my second stage ; but I shall describe it in 
 
 * I greatly rejoice over tlie -work of rny young friends, whose views are criticized above ; but 
 I have spent years over this kind of work, where they have spent weeks. There is such a thing 
 as " personal equation " to be made account of in scientific research ; and there is such a state of 
 mind in some workers, that they believe in no eyes but their own. 
 
Me. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 47 
 
 the 4th. This nucleus is found in the large interarticular plate, which is 
 seen between the proximal and distaltarsal masses in the inner {tibial) side 
 of the joint, and becomes thrust backwards when the ankle is complete: 
 the scaphoid is a centrale. This part was first seen by me to have this 
 interpretation early in 1886; and soon afterwards (independently) by my 
 son, T. J. Parker, in the embryo of the Aptcryx, It is very large in the 
 adult Buceros ruficollis, and is permanently anchored to the large inter- 
 articular fibro-cartilage. Even in the adult, where it serves a sesamoidal 
 function, it is permanently fixed between the astragalus and the part which 
 answers to the middle cuneiform bone.* 
 
 These two stages (Plate I., figs. 3, 4) show how the fore-paw of a 
 reptilian form begins to take on the ornithic characters. In its utmost 
 specialization (the whole limb becoming single down to the toes, and then 
 supported on four, three, or even two of these), the leg and the shank 
 being, as in the flamingo and stilt plover, extremely elongated ; and yet, 
 so exquisitely hinged and upheld, that one limb alone is sufficient for the 
 firm support of the whole body. This last result of the avian transforma- 
 tion cannot be too much admired. Nor are the varieties of the avian leg 
 and foot less excellent in this class, each member of which is a cunning 
 gymnast. Here in the duck we have the beginning of that modification of 
 the hind limb which has attained its utmost perfection in the loon 
 (Colymbus). Already, in stage 1, the hallux, or 1st digit, is being carried 
 away from the tarsus ; in stage 2, its arrested metatarsal (mi. 1 ) is attached 
 to the middle of the next (m.t. 2 ); still, even in this stage, the toes are 
 sprawling, and their metatarsals are free and diverging. In stage 1 the 
 digits (fig. 2, dg. 1 " 4 ) are soft, and their phalangeal segments very un- 
 defined ; in stage 2 (fig. 4) these are hardening and sub-dividing : the 
 remnant of the 5th {m.t. 5 ) can now be seen as a globular mass of softish 
 cartilage. Had it been developed with three or four phalanges at its end, 
 the reptilian foot would have been complete. 
 
 Even in the second stage the toes are amphibian as yet ; and the general 
 
 * See T. J. Parker, Proceedings, Eoyal Society, 1888, p. 487; and W. K. Parker, ibid., 
 1887, p. 58. 
 
48 Cunningham Memoirs. 
 
 web, which is retained for all but the 1st digit, is simply the common 
 expansion of the paddle, or hind oar, of a low, swimming creature. 
 
 Stage 3. — Embryo of Duck, after Twelve Days' Incubation. 
 
 In three days' growth the sprawling reptilian foot becomes almost typi- 
 cally ornithic : it is typically ornithoscelidan. What concerns us most now is 
 the further and further marking of the elements of the ankle-joint and instep, 
 tarsus and metatarsus. The bony shaft of the tibia (fig. 10, t.) is creeping 
 along the cartilaginous rod ; the fibula, also, and the femur are ossifying. 
 In the figure, the parts that form the ankle-joint are shown in a dislocated 
 state for illustrative purposes. As yet the tibia, proximal tarsal, and distal- 
 tarsal masses, and the metatarsals (fig. 10) are all distinct; but the three 
 elements of the proximal tarsal row are all fused together : the distal was 
 always undivided. The tibia, having starved the fibula, is dilated below 
 and deeply grooved, with extensor tendons in front : it is gently concave 
 behind. The curious knuckle which is strapped to it below has a double 
 condylar face below, and is like two heavy wheels joined by a broad axle. 
 This part is hollowed out, right and left above, for the lobes of the tibia to 
 fit into ; while towards the outer (or fibular) side, there runs upwards a 
 lone: tongue of cartilage, which is bound to the front of the outer tibial 
 ridge ; actually, this band reaches to the tibial ectostosis. On its tibial 
 side it has a square but convex bridge of newer and softer cartilage attached 
 to it, which passes over the deep tendon valley of the tibia.* 
 
 In the Papers, above referred to, neither Gegenbaur nor Huxley seem to 
 have dreamed of there being more than the astragalus in the large proximal 
 tarsal mass. The latter says (I. c, p. 20) of this part in the fowl : — " The 
 astragalus is a much depressed bone, with a concave proximal and a convex 
 pulley-like distal surface. A process ascends from its front margin in the 
 groove in the front face of the tibia. This process is comparatively short, 
 and perforated by two canals for the tibialis anticus and extensor communis in 
 
 * In my Memoir on Balaniceps, p. 343, I erroneously ascribed the formation of the tendon 
 bridge to the " ascending process " of the astragalus. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 49 
 
 the fowl ; while in the ostrich and emu it is extremely long and not so 
 perforated." Note here that the later band of cartilage had already become 
 ossified and fused with the short ascending process in the pullet's leg 
 described by Professor Huxley ; and here again the anatine type is seen 
 to correspond with the struthious, and to differ from the gallinaceous. I 
 trust that these figures and descriptions of mine will at least suggest to the 
 palaeontologist that he is not observing the primitive condition of the limbs 
 of Dinosaurs, nor, indeed, of the remains of any adult extinct reptile 
 whatever. 
 
 If, in the development of a duck's leg, such a complete fusion of the 
 three primary proximal tarsals takes place in three days (Plate I., figs. 4 
 and 10), surely some allowance may be made for the pre-natal transforma- 
 tion of an ornithoscelidan reptile. It is seen here (fig. 10, tb.,fbe., i.) that 
 the lesser fibulare has become completely fused with the larger tibiale, and 
 the intermedium with both : these three were all equally independent of 
 each other. The long tongue-shaped intermedium (/.) is united with the 
 fibular part of the common mass by a shorter, and to the tibial parts by a 
 longer tract of cartilage. The scaphoid, or centrale (c.) is a lunate wedge 
 of cartilage behind the tibial side of the joint, and is not, in the duck, 
 formed into solid cartilage as it is in the fowl. The great distaltarsal 
 (d.t.) has become completely formed, so as to show two concavities above 
 for the condyles of the proximal piece, and also a rounded intercondylar 
 process to fit into the hollow in the front of the upper piece ; behind, it has 
 sent down four ridges, the larger on the tibial side ; these form the tendon- 
 bridges and pulleys (fig. 11). The three main metatarsals (m.t. 2 '*) are seen 
 now to be closely applied to each other, and to be ossifying ; their round 
 tops fit into three concavities in the base of the distaltarsal. The fifth 
 metatarsal (m.V) is still to be seen as a small nucleus of cartilage : the first 
 has not been figured ; it has got down nearly to the end of the shank. 
 Even the condyle of the second, however, is higher up than either that of 
 the third or the fourth. This is an adaptive condition having relation 
 to the aquatic habits of the bird. 
 
 ROTAL IRISH ACADEMT CUNNINGHAM MEMOIRS, NO. VI. 
 
 [7] 
 
50 Cunningham Memoirs. 
 
 Stage 4. — Embryo of Duck, Fourteen Days' Incubation. 
 
 In this stage the intermedium (Plate I., fig. 12, i.) is still unossified ; 
 but this process begins directly after this time, that is on the fifteenth 
 day, or at the middle of the period of incubation. The tibia (t.) is still 
 distinct from the mass below ; the centrale can be seen as a definite nucleus ; 
 the fifth metatarsal (m.t. b ) is now confluent with the fourth. 
 
 Stage 5. — Embryo of Duck, Eighteen Days' 1 Incubation. 
 
 The ossification of the intermedium, which began on the fifteenth day, 
 is now nearly perfect, only the connective tract at tbe base being soft. The 
 ectosteal tract (fig. 13, ?".) begins as a thin bony ring round the bar, below the 
 middle, and rapidly runs to the apex below it : the tibiale and fibulare {tb., 
 fbe.) are still unossified, and are still free from the tibia, above : the toe of 
 the pedate base of the intermedium bounds the round intercondylar con- 
 cavity in which the knob of the distal tarsal fits : the tendon bridge over 
 these is now well developed. 
 
 Stage 6. — Duckling, Three Days old. 
 
 In the middle of the first week after hatching, the sections through the 
 ankle-joint show a bone in each of the pulley-like elevations of the proximal 
 tarsal mass ; and also one in the centre of the great distaltarsal. The 
 tibia is still distinct from the former, and the metatarsals from the latter 
 (Plate I., figs. 14, 15, *., tb., fbe., cl.t., m.t.). 
 
 In one figure (14) the tibiale is cut through, but the lower bony centre 
 is not reached; in the other (15), both the fibulare and the metatarsal 
 centres are exposed ; these are all three of the normal kind of bony deposits 
 for these short segments of the limb. They are " central endostoses," and 
 are a long while coming to the surface ; so that, if the ascending process 
 were in reality a mere periosteal growth of the double proximal tarsal, two 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 51 
 
 things would have to be proved concerning it : firstly, that it did not 
 appear until the bird was fully adult ; and, secondly, that it had not its 
 own osseous centre. The merest tyro in anatomy knows that this is 
 true. In the duckling of the first week the "centrale" has degenerated 
 into a mass of fibro-cartilage, forming part of the tendon sheaths at the 
 back of the joint. Water-birds do not conserve this element as an ossified 
 and distinct piece. 
 
 The Hind-limb of the Swans (Cygnincc). 
 
 In the almost ripe embryo of Cygnus nigricollis (Plate III., fig. 8, and 
 Plate IV.) the ankle-joint is quite like that of the fifth stage of the embryo 
 duck, except that the intermedium («.) is shorter. After hatching, the 
 growth of the swan's young is evidently slower than that of the duckling — 
 cygnets of a month old being not much more advanced in this respect than 
 ducklings of the first week. Happy in the possession of two of these, 
 which were about equal in size to a teal ( Querquedula crecca), I can show 
 that, whilst the intermedium begins to ossify by the middle of the incu- 
 bating period, the central endostosis, forming the rudiment of the tibiale, 
 fibulare, and distal tarsal, has only reached the perichondrium at the end of 
 a month after that period (Plate V., figs. 8-10); no periosteal deposit is 
 possible as yet ; and, even afterwards, the double mass (when the tibiale 
 and fibulare are completely fused) is covered with articular cartilage, 
 except where it has become fused with the tibial shaft-bone. Thus, the 
 formation of the ascending process, as a periosteal outgrowth, is impossible. 
 
 The rest of the hind-limb in the swan, and in the Anatidse generally, 
 is constructed for swimming, and even for diving, in the clucks, and 
 especially the mergansers. The two inner and larger post-tarsal ridges 
 form a bridge over a flexor tendon, as in the fowl : the tarso-metatarsus is 
 compressed laterally : the fourth digit is elongated, the second and first 
 elevated, and the latter is small and free. 
 
 [7*] 
 
52 Cunningham Memoirs. 
 
 Wing of Embryo (* ripe) of Falkland Island Goose (Chloephaga 
 
 poliocephala). 
 
 When Dr. R. W. Shufeldt called the displaced first distal tarsal " pen- 
 tosteon," five carpals were known in the young bird ; although, in almost 
 every case, only the two proximal pieces remain distinct. 
 
 Dr. Morse* satisfied himself that the so-called "ulnare" was a double 
 nucleus. And he was right : it is so, morphologically ; and is, not unfre- 
 quently, actually subdivided into two, or even three nuclei. In a Paper, 
 soon to be printed, f I have shown that the " radiale," also, may be in two 
 pieces : for a time it is so in Opiosthocomus, the subject of that Paper ; and 
 I find it so, also, in Falco tinnunculus. 
 
 The subdivision of the ulnare is seen in two of the most terrestrial forms 
 of the Chenomorphoe, namely, in this goose and in the screamer ( Chauna 
 chavaria). This is the more interesting, because the long-legged terrestrial 
 geese are very apt to have spurs on their wings [e.g. Chenalopex, Plectrop- 
 terus) ; and these spurs have their highest development in the unwebbed 
 Palamedida3 — birds with cultratc bills. Thus, whilst on one hand the 
 Chenomorphse are walking, or, at most, wading birds ; on the other, the 
 mergansers have certainly a smack of both the cormorant and the diver in 
 their nature. This makes it extremely difficult to conceive of the whole 
 bundle of Chenomorpha3 as branches of one stem. 
 
 In the ernbryo of Chloephaga poliocephala the claws are well developed in 
 the wing (Plate V., figs. 12 and 13), that on the index (dg. 2 ) being especially 
 long. The parts at the lower hinge of the wing are as remarkable for their 
 great number as these parts in an adult bird generally are for their fewness. 
 The radiale (re.) is single; but the thick U-shaped ulnare (ue., c. 1 , tv) has 
 both its crura segmented across, almost perfectly, to form an outer and an 
 inner " centrale " (fig. 14, c. 1 , c.' 2 ). At this stage the three distalcarpals 
 (d.c. 1 ' 3 ) are clearly marked out ; and on the edge of the third metacarpal, on 
 
 * Loc. cit. f In the Transactions, Zoological Society of London. 
 
Me. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 53 
 
 its flexor side (figs. 14, 14 a ), there is a distinct rudiment of a fifth meta- 
 carpal (m.c. 6 ). On the proximal part of the second metacarpal, at the outer 
 face of its ulnar edge, there is a distinct semi-lanceolate accessory cartilage 
 (m.c. 2 1 ) : the accessory part to the proximal phalanx of the digit (dg. 2 1 ) has 
 coalesced with the main piece on its ulnar side, and is ossified by it, not 
 independently. The sub-division of the ulnare is not so evident on the 
 right side as on the left. When the spur is formed on the " trochanter" of 
 the first metacarpal (m.c. 1 ) in some of the geese, there is in this case a con- 
 siderable tract of fibro-cartilage ready for any such adaptive growth. 
 
 Whilst the peculiarities of this embryo, and of that of the kestrel, were 
 the only types in which I had seen this remarkable sub-division of the 
 radiale in one, and of the ulnare in the other, they caused me much 
 anxiety : now I find that this is not so rare a condition as I had sup- 
 posed. 
 
 But for a quarter of a century I had been aware of a divided " ulnare" 
 in Chauna chavaria. In that bird, on the left side, there are two proximal 
 carpal bones attached to the ulna (Plate II., fig. 13, tie., c.)\ the outer is 
 the outer centrale, and the inner is the "ulnare" proper: this is one-third 
 larger than the other. Here, again, this peculiarity is seen on the left side, 
 and not on the right. 
 
 In the other Palmipeds we shall see parts of the wing-skeleton that have 
 hitherto been quite unnoticed. We are only just waking up to the fact 
 that the things that now are have not been so always since the foundation 
 of the world. 
 
 In the cultrate Palamedidse, and in some of the lamellirostral forms, 
 the wing has spurs similar to those on the shank of the Phasianidse. Dr. 
 Sclater* quotes, with approbation, the views of Mr. J. Amory Jeffries, t 
 His words are : — " Mr. Jeffries shows definitely, for the first time so far as 
 I can make out, that the spurs which are in some cases found on the wings 
 of birds are of an entirely different nature from the claws also met with on 
 
 * Ibis, 1886, p. 147. 
 
 f "On the Claws and Spurs on Birds' Wings": Proceedings, Boston Soo. Nat. Hist., vol. 
 xxi., p. 301. 
 
54 Cunningham Memoirs. 
 
 the same organs, and have in fact nothing whatever to do with them." In 
 a note on this same page, Dr. Sclater says : — " Even so recent an authority 
 as Dr. Selenka* has confounded together the spur and claw of birds. His 
 account of the subject contains several serious misstatements, and is 
 obviously not based on his own examination. Owen's ' Anatomy of Verte- 
 brates ' (cf., op. cit. II., p. 74) likewise confounds claws and spurs. It must 
 be even admitted that Nitzsch (usually a model of accuracy, and the first 
 scientific describer of the claws of birds) did not quite understand the dif- 
 ferences between claws and spurs."f 
 
 I must also, myself, confess to having confounded claws with spurs in 
 my Paper " On Bala3niceps,"J and also in that " On Gallinaceous Birds 
 and Tinamous,"§ I have put the hallux as the second toe, considering 
 the spur of the cock to be the abortively developed first toe. 
 
 That error was corrected by Gegenbaur,|| and his views were adopted 
 by Huxley. *\ The hind-toe or hallux does certainly correspond with 
 the innermost, or first toe, in a lizard's hind-foot, just as the pollex of the 
 bird corresponds with the innermost digit of the fore-foot of a lizard. The 
 normal number of phalanges determines this, namely from two in the first 
 to five in the fourth, and then a diminution in number in the fifth. 
 
 But this matter cannot be settled and made sure for ever to science by 
 the study of adult birds. If Dr. Sclater had compared the wing of Chauna 
 derbiana (op. cit., p. 150, fig. 2) with Dollo's figures of Iguanodon bernissar- 
 tcnsis** or even with some of my figures of the early state of the digits of 
 the wing, ft his sense of certainty would have yielded to the confusion of 
 
 * Bronn's " Thier-Reieh " : Aves, p. 75. 
 
 t See his " Osteographische Beitrage, No. 5": Ueber das Nagelglied der Fliigelfinger, 
 besonders des Dauraens : Leipzig, 1811. 
 
 \ Transactions, Zoological Society, vol. iv., Plate LXVI. 
 
 § Ibid., vol. v., Plate XXXV. 
 
 || " Vergleichend-anatoniische Bernerkungen uber das Fussskelet der Vogel " : Arcbiv. fur 
 Anat. und Phys., 1863. 
 
 ^1 Proceeding's, Zoological Society, 1867, p. 417. 
 
 ** Bull. Mus. Roy. Hist. Nat. Belg., t. i., Plate IX., figs. 2, 3. 
 
 ft Philosophical Transactions, 1888, B., Plate LXIL, figs. 1, 2. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 55 
 
 mind attributed by him to Owen and Nitzsch. In that huge extinct reptile, 
 with its extremely avian hind-quarters, both the pollex and the fifth finger 
 diverge at a right angle from the rest. If the horn-core and the small bone 
 at its base had been anchylosed to the other parts, nothing would have 
 appeared more certain than the precise homology of that pollex with the 
 upper spur in Palamedea and Chauna. The difficulty does not, however, 
 cease here. In a continuation of his valuable Paper,* Dr. Sclater shows 
 that the large spur on the wing of the spur-winged goose (Plectropterus 
 gambensis) is on a projection of the racliale, or inner proximal carpal. 
 Nothing, to those who are satisfied with adult anatomy, could be clearer 
 than this proof that the spurs are of an entirely different nature from the 
 claws also met with on the same organs, and have, in fact, nothing what- 
 ever to do with them. 
 
 But we must, as the saying is, " go slowly that we may make the more 
 speed." I would remind Mr. Jeffries and Dr. Sclater that, in the evolution 
 of the cheiropterygium from the ichthyopterygium, claws are a late specializa- 
 tion. Only Dactylethra, amongst existing Amphibia, possesses them. In 
 the Reptilia, as in Dactylethra, the straight nailless terminal phalanges grew out 
 into the skin-fold, and there received a horny covering, both the dermal 
 layer and the terminal phalanx becoming covered, and so forming a 
 hooked claw. 
 
 But the normal digits of the highly specialized pentadactyle cheiroptery- 
 gium are not the only parts we have to deal with in the limbs of birds and 
 mammals. Neither birds nor mammals are the descendants of true reptiles, 
 but of much more ancient and generalized types. 
 
 I find, taking the birds as a whole — in this bird and in that — a row of 
 cartilaginous nuclei inside, or in front of, the normal first digit, or pollex. 
 These I shall describe in a Paper succeeding the present. Not only these 
 segments of a " pre-pollex," but intercalary segments are also common in 
 the developing wing of a bird — feeble f orkings of the digits ; a reappear- 
 ing, or rather a lingering, of vestiges or remnants of some archaic polydac- 
 tyle limb. In the common fowl the core of the cock's spur is at first a solid 
 
 * Ibis, 1886, pp. 300-301, fig. 3. 
 
56 Cunningham Memoirs. 
 
 fibro-cartilage — a " pre-hallux " : it fuses with the second metacarpal after 
 it has become ossified. 
 
 Now, the presence of two spurs on the same limb in the shank of 
 Polyplectron, and in the wing of Chauna,* seems at first blush to decide the 
 merely adaptive and, as it were, accidental nature of these spurs. My 
 answer to this is that there are two phalanges which appear between the 
 pollex and index in birds ; and that the distal of these two segments is 
 present in by far the greater number of Passerine birds. That segment is 
 a triangular plate of true hyaline cartilage, autogenously ossified by 
 endostosis, and becomes fused with the ectosteal sheath of the second meta- 
 carpal, near its lower end ; and is manifestly the true homologue of the 
 horn-core of the distal spur in the Palamedidse. 
 
 The Alcid^e. 
 
 This palsearctic family, which has only lately lost its chief — Alca 
 impennis — is still rich in forms ranging in size, if we take in the great lost 
 species, from a large goose to a small gosling ; for Ciceronia pusilla scarcely 
 exceeds the size of the latter. 
 
 These birds are the isomorphs of the nearctic penguins (Spheniscidas)*; 
 and, in the case of the great auk, the approach of the northern to the 
 southern type was very close. 
 
 As to the penguins, they are a much more isolated type than the auks 
 and guillemots, and are also much more uniform. Specialized to the 
 uttermost in one direction, they are nevertheless evidently archaic. The 
 tendency of the Alcidpe is in the same direction : they appear, however, to 
 have begun to modify in this direction later than the penguins, and the 
 transformation is only partial. This, however, is pure conjecture. Pro- 
 fessor Huxley's " Classification "f breaks down most among these water- 
 birds. His " Cecomorphse " are a promiscuous flock of Palmipeds driven 
 together by the "whiff and wind" of his taxonomic force. If it pleases 
 
 * Sclater, op. cit., p. 150, fig. 2. 
 
 f Proceedings, Zoological Society, 1867, pp. 415-472. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 57 
 
 him to call the group the gull-form, he must not be surprised if the next 
 classifier should scare them all apart again. 
 
 Dr. Marsh did this unconsciously ; for his toothed birds show, if they 
 show anything (and they are the most lucid revelation we have had on this 
 subject as yet) that the divers and the gulls were as far apart in the secondary 
 epoch as they are now. The Ichthyornis is evidently an archaic toothed 
 gull ; and the Hesperornis, which anticipates the modern terrestrial 
 Ratitse, has, like its nearest living relatives, the grebes and loons 
 (Podicipitidse, and Colymbidae), cylindroidal vertebrae down to its 
 sacrum. Ichthyornis, a Carinate, has its pre-sacrals amphiccelous — a 
 condition scarcely improved upon by the existing gulls in their hinder 
 dorsals : their cervicals arc cylindroidal. This modern group of the 
 Alcidge, like the existing gulls, have opisthoccelous dorsals ; and so 
 have the penguins and the plovers, the cormorants and the darters ; but 
 grebes and loons, like Hesperornis, have the whole pre-sacral series 
 cylindroidal ; in which they agree with the modern Ratitae on one hand, 
 and with the petrels and all the " Steganopods " or Tolipalmatse, except 
 the cormorants and darters (Phalacrocoracida?) and Plotidse. 
 
 In respect of the dorsal vertebra? the Alcidaj and LaridaB agree, and 
 their skull* is very similar fundamentally; but so, also, is that of the 
 aberrant Limicolse, e.g. Ononis, Attagis, and Thinocorus ; and the Rallidas, 
 also, come very close in this respect. The fact of the case is that, in great 
 numbers of those schizognathous birds that abort their basi-pterygoids, 
 there is a wonderful conformity in this respect. 
 
 But the skull of the penguins is also one of the same type ; it is some- 
 what more archaic certainly ; but there is nothing in that part, nor in the 
 rest of the bird, it seems to me, sufficient to warrant the separation of that 
 one family into a sort of order — the " Spheniscomorphse " — whilst gulls, 
 skuas, petrels, auks, guillemots, loons, and grebes are put together by 
 force into a sort of " happy family " : their harmony will end the moment 
 the personality of the " keeper" ceases to dominate them. 
 
 * See Huxley, op. eit., p. 430, figs. 10, 11. 
 
 EOYAL IUISH ACADEMY CUNNINGHAM MEMOIRS, NO. VI. [8] 
 
58 Cunningham Memoirs. 
 
 In some respects the gulls and auks agree ; they are as unlike, on 
 the -whole, as it is possible for two groups of water-birds to be. 
 
 The Morphology of the Alcid^e.* 
 
 The Cranium in Uria troile. 
 
 Stage 1. — Skull of Embryo of Uria troile, One-third ripe. 
 
 The chondrocranium, at this stage, is fully formed (Plate VI., fig. 1). 
 The basal part is the most instructive ; the other regions will come under 
 notice in the more advanced stages. f 
 
 The transitory, as well as the permanent, parts of the endocranium are 
 well developed ; much of the latter will undergo osseous transformation. 
 The chondrocranium, at present, has some little likeness to that of a skate, 
 the skull proper being so short, and the pre-nasal rostrum so long ; but this 
 is a high skull, like that of a perch, and that of the skate is a low one. 
 Here the brain is tilted upwards in front, and lies on the coping of a large 
 wall : in the skate, as in the Amphibia, the brain lies down on the flat 
 basi-cranial floor. The chondrocranium has not yet begun to ossify ; the 
 notochord (nc.) is still large ; but the parachordal tracts have united across 
 it, have coalesced with the cartilaginous ear- capsules, and have sent 
 upwards lateral growths that have met, right and left, and become con- 
 fluent, over the hind brain. Behind, the double tract of cartilage has 
 formed the almost hemispherical occipital cond}de (oc.c.) ; and, in front of 
 
 * For the osteology of the same parts of the embryo of Alcidoe, see my " Shoulder-girdle and 
 Sternum " (Plate XVIL, figs. 10-14, pp. 146-148) ; and of the adult bird, see Owen, " On Alca 
 impennis," Transactions, Zoological Society, vol. v., Plates LI.-LIL, pp. 317-335 ; and It. W. 
 Shufeldt, "Osteology of Arctic and Antarctic Water Birds." — Journal of Anatomy and Phy- 
 siology, vol. sxiii., Plates I.-V., pp. 1-39; ibid., Plates VII.-XL, pp. 165-18G ; ibid., pp. 
 400-558. 
 
 f For figures and descriptions of the very similar skull of Gavia ridibunda, see Transactions, 
 Linnean Society, series 2, vol i., Plates XXVL-XXVIL, pp. 140-151. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 59 
 
 this, and further outwards, we see the passages for the hypoglossal (xii.), 
 and vagus and glossopharyngeal nerves (ix., x.). 
 
 The auditory capsules occupy a very large space in the sides and hase 
 of this delicate semi-transparent chondrocranium. The lagenar (««.), and 
 the canals (a.s.c., h.s.c., p.s.c.) shine through the thin, clear walls. In front 
 of these captsules the base of the skull suddenly closes in ; the notochord is 
 lost to view, for it ascends into the post-clinoid wall (see in stage 3, fig. 8, 
 p.cl.). In front of that wall there is a round opening — the pituitary 
 space, which receives a secondary floor, but is not, as in our cranium, 
 floored with cartilage — the seat of the " sella turcica." That open hole 
 was formed by the growth of the trabecular round the pituitary involu- 
 tion ; there they met, and coalesced with, the parachordals or investing 
 mass enclosing the notochord behind. Meeting in front of this open 
 space, the trabecular run forwards, and, apparently, at this stage, form the 
 long, thick, rounded balk of cartilage which runs forwards to the end of the 
 beak. But a little in front of the pituitary space there was formed a 
 median cartilage, which wedged itself in between the other two, and can 
 therefore be fitly called the inter tralecula. The paired trabecular only run 
 half way to the end ; flattening out, they grow upwards and help to form 
 the orbito-nasal partition wall (see, in 3rd stage, fig. 8, tr.,p.e., s.n.). The 
 trabecular, in some cases, send out flat cornua where they end.* I 
 do not see these parts in Uria. The foremost third of the long wall is 
 free ; it has no wall growing upwards from it : it is a large Ratine pre-nasal 
 rostrum. Just when it is becoming free, it is somewhat twisted, as also 
 is the primary mandible below (fig. 2, mk.). I shall refer to this in the 
 next stage. The large alisphenoidal, and the aborted orbito-sphenoidal 
 wings will be described in the 3rd stage (fig. 8, al.s., o.s.). 
 
 Instead of the direct basi-cranial outgrowths for articulation with the 
 pterygoids, as in lizards and the Ratitar,t these birds, like the fowl and 
 most other Carinatar, develope separate remnants of those basi-pterygoid 
 outgrowths (fig. 1, b.pg.). In these, and many other birds, these parts, 
 
 * See in Chick, Philosophical Transactions, 1869, Plate LXXXI11., fig. 4, s.v.l. 
 f See Philosophical Transactions, 1866, Plate VII., figs. 2 and 4, tip. 
 
60 Cunningham Memoirs. 
 
 and the joint formed by them and the pterygoids, is only a temporary 
 structure ; and in many of the passerines the remnants themselves are 
 suppressed.* 
 
 The pier of the first visceral arch — the quadratum (</.) — is a large 
 segment, and very amphibian in the bird, as in the Chelonia. Here we 
 see that its pedicle or primary swinging point, the orbital process is 
 free and rounded; its secondary head, or "otic process" is large and 
 bilobate, obliquely. Below, the short, thick, main bar ends as a sinuously 
 convex condyle for articulation with the next segment of this inverted 
 arch — the articulo-meckelian rod (fig. 2, m.k.). That rod, right and left, is 
 almost as solid as the great cartilaginous skull balk : it is a long, terete, 
 sinuous rod, gently lessened in front, rounded at its end, and lobate 
 and scooped behind for articulation with its own upper segment : it has, 
 like its counterpart in the marsupial Mammals (the future malleus), both 
 an internal and an external angular process (i.a.p., p.a.p.). The mecke- 
 lian rods do not coalesce distally, or in front, as they do in the Mammalia, 
 but remain free as long as they exist, as in lizards and snakes. f In 
 morphological language, the quadrate is the first epi-branchial, and the 
 articulo-meckelian rod the first cerato-branchial. They were gill arches. 
 
 The second visceral arch — the hyoid — is half suppi'essed. Its upper- 
 most segment, as in the Amphibia and Reptilia, has been dominated by 
 the organ of hearing, and is aborted and specialized : this part is the 
 columella (fig. 1, co.) : it has a dilated proximal, and a trifid distal 
 end. In morphology it is a pharyngo- branchial segment. In some 
 birds a distinct epi-branchial segment is formed, and coalesces with the 
 lower ray of the columella — the " infra-stapedial " : distally, the cerato- 
 hyal appear in the hypo-hyal region. The right and left cerato-hyals 
 (fig. 3, c.hy.) are terete, lessen forwards, and meet each other in the sagitti- 
 form tongue. Between and behind these the old basi-branchial reappears 
 (b.lr.) : it is thickest towards the front, and lessens behind, where it ends 
 
 * Monthly Micr. Jour., March 1st, 1873, Plates VIII.-X. 
 
 f Philosophical Transactions, 1878, Plates XXVIII. , XXIX. ; and ibid., 1879, Plate 
 XLL, fig. 3, mt. 
 
Me. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 61 
 
 free and pointed : it represents several median segments. One branchial 
 arch, which answers to the first gill-bearer in osseous fishes (fig. 3, br. 1 ), is 
 developed. It is in two segments ; the larger is the distal ; this is ossifying : 
 the lesser is still soft, and is free above ; it curls round behind the occiput. 
 I have not described the nasal capsules in this stage : I shall refer to them 
 in the next. 
 
 The ectocranium, at this stage, has all its primary centres of ossifica- 
 tion started : they are creeping tracts of osteoblasts forming in the sub- 
 cutaneous web, and are very similar in character, in form, and in relation 
 to those which are formed in the chondrocranium of an osseous fish. Indeed, 
 it is with the Ichthyopsida generally, and not with the existing Reptiles, 
 that the developing skull of a bird has to be compared, if its interpretation 
 is to be made sure. Yet, no osseous fish or existing amphibian, and no 
 reptile now living, has such an extremely prognathous face as this. As the 
 primary pterygopalatine arcade (pg.pa.) is almost entirely suppressed, the 
 pterygoids and palatines are here reduced to the condition of mere parostoses 
 like the premaxillaries, maxillaries, jugals, and quadrato-jugals (px. mx., 
 q.j.). All ascent in the Vertebrata skull is attended with the fading of 
 the chondrocranial parts, and the flourishing of the ectocranial elements. 
 The dominating splints of the upper face are the premaxillaries (px.), as m 
 typical osseous fishes: these use the Raiine pre-nasal rostrum (p.n.) as a 
 model, then destroy it by their own overgrowth. The maxillaries (mx.) 
 are mere " ossa mystacea " lying behind and within the premaxillaries: 
 they have already formed an angular process, the part that overlaps the 
 jugal arch, and also their palatine process — maxillo-palatine (mx.p.) — a 
 curved retral style, with its curved outline inwards. Between these two 
 processes the palatine {pa.) sends its styloid fore-part: it then dilates, 
 bends outwards, and sends inwards an ascending process to bind upon the 
 basis cranii, and with its fellow to hold the vomer as in a vice. Overlapping 
 the inner side of these bones, behind, we see the falchion-shaped pterygoids 
 (pg.) that are already cupped at their other ends, and are fitted to the knob 
 on the quadrate : this knob is a small stump of what was, in the ichthyop- 
 sidan ancestor, a long pterygopalatine cartilage. The quadrato-jugal {q.j.) 
 hooks itself into the outer face of the quadrate (q.) behind, and overlaps 
 the jugal (/.), and the third or jugal process of the maxillary (mx.) in front. 
 
62 Cunningham Memoirs. 
 
 Perfecting the palatomaxillary framework in front, we see the vomer 
 (v.); at present it is in two halves, which are mixing their osteoblasts under 
 the intertrabecular balk ; these moieties, in front, reach to the middle of 
 the maxillo-palatine, and, behind, touch the ascending processes of the 
 palatine. 
 
 Outside the quadrate, the squamosal (sq.), its proper splint, is walling 
 in the temples, right and left : out of sight, in this view, the nasals, frontals, 
 and parietals are rapidly forming : they will be described in the next stage 
 (Plate VII. and Plate VI., figs. 4, 5, n., /., p.). On the lower jaw 
 (Plate VI., fig, 2) four splints are forming, the dentary splenial, supra- 
 angulare, and angulare (d.sp., s.ag., ag.) : there is no distinct coronoid. 
 
 The last parostosis to be described is the first to appear in the develop- 
 ment of the skull in the Vertebrata : this is the parasphenoid. To support 
 the huge hypertrophied mass of hyaline cartilage in those selachian 
 Ganoids, the sturgeons (Acipenseridce), with their imperfectly developed 
 vertebral chain — not fairly differentiated from the cranium, a huge 
 bony splint, is formed, a hard balk under a soft balk for support and 
 strength. This is the first appearance, morphologically speaking, of the 
 parasphenoid.* 
 
 Passing to the higher Ganoids and Dipnoi, and thence to the Teleostei, 
 on the one hand, and the Amphibia on the other, we see the parasphenoid 
 becoming dominated by the cranium, and having no sub-vertebral develop- 
 ment. All at once, in existing Reptiles, it is fading away, and is quite 
 lost in some lizards (e.g., Trachydosaurus), and in the Chelonia. 
 
 It is to the extinct Reptiles, and to the Amphibia, that we must look 
 for anything like what is found in the basis cranii of a bird ; and in the 
 former class, not to the Ornithoscelida, with their bird-like hind-quarters, 
 but to those quasi- Cetaceans, the Ichthyosaurs. 
 
 As a rule, the parasphenoid is like a dagger, with its blade, guard, and 
 handle. In some Anura (e.g. Pseudis)| there is no handle to this bone : 
 
 * This is Professor Huxley's term (see "Elem. Comp. Anat.," 1864, p. 170) — a term which, 
 in Morphology, is " a nail in a sure place." This is the bone which, in fishes, was to be divided 
 by Owen's saw ! That act of violence was not needed. 
 
 f See Philosophical Transactions, 1881, Plates II., X., XI., XII., pa.s. 
 
Me. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 63 
 
 this is what is seen in this embryo of Uria (Plate VI., fig. 1, pa.s.). Here 
 the blade is very narrow, being developed later than the guard, which 
 has a right and left centre of ossification in birds.* In the Amphibia, 
 when not in one centre, this element has the point of the blade separate. f 
 
 Stage 2. — Skull of Embryo of Uria troile, two-thirds ripe. 
 
 In this stage (Plate VI., figs. 4-7, and Plate VII.) the general has 
 rapidly passed into the special ; this is in a typical schizorhinal skull, with 
 a sharp face, and having the nasal (n) bones split almost up to their frontal 
 or hinder margin. It is now a pattern-form, so to speak, for all those 
 skulls that with this form of the nasals are permanently schizognathous, as 
 in this bird and in a large number of the swimming and wading forms — 
 gulls, grebes, loons, rails, plovers, cranes, &c. ; and also for many that 
 become desmognathous, as the ibises, spoon-bills, storks, &c.J 
 
 The endocranium (Plate VI., fig. 4) now shows the normal osseous 
 centres ; the oblong basi-occipital (b.o.) has formed round the notochord ; 
 at a distance from it the ex-occipitals (e.o.) are seen as large square plates, 
 enclosing the nerves ; and, at a greater distance, the double supra-occipitals 
 form a keystone to the occipital arch. The basisphenoid (b.s.) is not, as 
 in Reptiles and Mammals, an independent bone, but, as in certain. Urodeles, 
 the parasphenoid (pa.s.) grafts itself upon the cartilage at that part : the 
 alisphenoids (Plate VII., al.s.) are large cartilaginous wings, with a thick 
 sphenotic outgrowth (sp.o.). A large pyriform fenestra (i.o.f.) is formed in 
 the high, interorbital wall : above the narrow upper end of this oblique 
 span the presphenoidal region (p.s.) is somewhat lipped ; these lips are the 
 arrested orbitosphenoids (o.s.). Running under the wall, and becoming 
 
 * See Philosophical Transactions, 1869, Plate LXXXIL, fig. 2, b.t. 
 
 f Philosophical Transactions, 1881, Plate VIII. , fig. 2, pa.s. 
 
 \ All such characters as holorhinal and schizorhinal, schizognathous and desmognathous, 
 are valuable and useful in classification, up to a certain point. The exceptions, however, are the 
 most instructive forms, such as the flamingo — an anserine ibis, and psophia — a tinamine crane : 
 these are exceptionally holorhinal among schizorhinal tribes. 
 
64 Cunningham Memoirs. 
 
 free at the fore end, the trabecular balk, in its fore half, where it is simply 
 the azygous intertrabecula (Plate VI., fig. 4, i.tr.), becomes twisted : it is like 
 a worm struggling to be free ; and, indeed, it is becoming fast bound by the 
 enclosing parostoses, that conquer and then destroy it, after building them- 
 selves upon it. This rod is only two-thirds as thick as it was in Stage 1 
 (fig. 1, p.n.). Seen laterally, the nasal labyrinth is large, and is quite 
 cartilaginous at present. In all birds the perpendicular ethmoid (p.e.) is 
 greatly overgrown, and, in its ossification, thrusts the presphenoid upwards, 
 by meeting and uniting with the basisphenoicl : it surrounds all but the 
 hinder and upper part of the great fenestra (i.o.f.), and reaches, in front, to 
 the craniofacial hinge (see Stage 3, Plate VI., fig. 8): beyond that part the 
 mesethmoidal wall is differentiated into the septum nasi. The great 
 appearance of complexity in the outer walls of the nasal labyrinth only 
 partially corresponds to what is found within. In front of the orbits the 
 cartilaginous roof, continuous with the wall, is folded over, and a flat 
 plate — "pars plana" or antorbital — is developed as the back wall of the 
 labyrinth : its pointed anteroinferior corner is free, and is the rudiment of 
 the ethmo-palatine bar of a frog, or other Amphibian — Anuran or Urodele. 
 The simple coiling downwards and inwards of the aliethmoids, and the 
 aliseptal coils which form a scroll of less than two horns, the inferior 
 turbinal (Plate VII., Lib.) are like those of the duck or fowl.* The 
 alinasals or valvular folds (al.n.) that grow from the fore part of the septum, 
 and in front of it, answering to our " alas nasi," are long and simple : the 
 external nostril (e.n.) which they form is obliquely sub-terminal and 
 reniform. 
 
 The quadrate (q.) is now ossifying ; a largo ectosteal sheath has formed 
 on it; and a flat ectosteal plate (fig. 6, ar.) has applied itself to the proximal 
 part of the articulo-meckelian rod (mk.) on its inner side ; the endosteal centre 
 which completes the articulare is formed afterwards. Answering to the 
 single intertrabecula above, the paired meckelian rods below are longer and 
 slenderer than in the last stage. Like that rod they are strangely twisted, 
 but still more so (as if writhing within the splints) ; and, had they belonged 
 
 * See Philosophical Transactions, 1869, Plate LXXXVI. 
 
Me. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 65 
 
 to the embryo of a captive, or even to that of a less domestic bird, I should 
 have set down this structure to the account of teratology. That view is 
 inadmissible ; equally so is that of their having any teleological meaning. 
 We are thus shut up to an ontological hypothesis. The moderate beak of 
 the guillemot, with its horny sheath, has manifestly been modified from a 
 much longer and a dentiferous beak — one like that of Marsh's toothed birds, 
 and not unlike that of the long-faced Pterodactyles. 
 
 If this be the case, we may claim for these embryonic stages an impor- 
 tance equal, in science, to the various adult forms that are being slowly 
 revealed to us in palaeontology. As a morphologist " I magnify mine 
 office," and boldly put my stages side by side with my friend 0. C. Marsh's 
 adult extinct forms. 
 
 This stage and the next are good for showing the normal form of the 
 splint bones or ectocranium of a carinate bird — so unlike those of a Ptero- 
 dactyle, or of Archasopteryx, and which are a marvellous refinement of 
 such superficial bones as we see in the skull of the existing Ratitas. Once 
 attained, this type of growth of the outer skull-case is not in any impor- 
 tant degree departed from The figures here given might serve as a 
 generalized diagram for the ectocranium of any one of the existing 
 Carinatse, which number more than twelve thousand species. If this fact 
 does not prove that all these forms had one father, it at least suggests that 
 they all arose from very similar ancestors. 
 
 The very peculiar form of a sauropsidan cranio-facial apparatus was 
 a necessity that arose when the fore-paws were manacled and made useless 
 for prehension in types that were to rival all others in intelligence and 
 skill. We have on one hand, in the beginning, the dull, cold, aquatic quasi- 
 salamandrian ancestor, and, on the other, in these latter days, the lively, 
 hot-blooded songster — that most cunning winged architect. Thus, as the 
 beak has to become the hand, and the neck the arm, the upper face has to 
 be hinged upon the skull proper, and the lower face adapted, in its free 
 mobility, to its elastic upper counterpart.* 
 
 In the fixed face of man, or any other mammal, the face and cranium 
 
 * "For a description of this apparatus, see Bell's " Human Hand," pp. 172-174. 
 
 ROYAL IRISH ACADEMY. CUNNINGHAM MEMOIRS, NO. VI. [9J 
 
66 Cunningham Memoirs. 
 
 make one undivided skull ; the ecto-cranial plates are all firmly tied one to 
 another, to form the solid whole. Here in the bird the extremes meet, of 
 free mobility in the face and palate, and of complete fusion, by loss of 
 all the sutures, in the proper cranial part ; but the original form and con- 
 dition of the splint-bones is quite similar in both regions. These parostoses 
 are extremely thin and elastic in this second stage ; but they have already 
 almost a reptilian completeness, and fit one to another in perfect adapta- 
 tion. The once double premaxillary {px.), in a manner truly avian, sends 
 its nasal processes up to the forehead, between the split nasal bones (Plate 
 VI., fig. 5, «.), the upper fork of which binds, right and left, upon those 
 splinty processes. Below, in the fore-palate (fig. 4), the jn-eniaxillary is 
 sharply split into a dentary and a palatine process on each side ; and the 
 great maxillary (m.v.) wedges itself in between these styloid forks. That bone, 
 becoming a triangular plate, then gives off, externally, a short angular and a 
 long and slender jugal process; and, on its inside, is produced into a larger 
 retral hook, the maxillo -palatine process (mx.p.). The jugal arch, exter- 
 nally, is finished by the long and slender jugal and quadrato- jugal (/., gy'.), 
 the former overlapping the other two splints, the latter hooking itself into 
 the side of the quadrate (q.). 
 
 The palatines (pa.) are rather broad laths, bent a little outwards, broad 
 behind, and styliform in front ; the style runs along the inside of the 
 palatine process of the premaxillary. The pterygoids (pg.), like two short 
 pieces of " knee-timber," tie the palatines to the quadrate bones; they are 
 only half the width, and one-third the length, of the latter ; and, bending 
 inwards at their middle, abut upon the temporary basi-pterygoids (b.pg.). 
 In front, the pterygoid is styloid, and lies upon the palatine; that part 
 undergoes osseous segmentation, and is then the temporary mesopterygoid ; 
 it then ankyloses with the palatine: behind, the pterygoid has a cupped 
 facet, which forms a joint with a little ball on the quadrate. Returning to 
 the palatine, we find, on its postero-internal edge a small keel, and outside 
 it, a fossa : this structure is for muscular attachment : above, and in front 
 of those keels, right and left, we see the styloid ascending process. The 
 vomer (v.) wedges itself in at that part, and is clipped by these processes ; 
 it is a large, long, oblong bone, notched in front, and split in more than its 
 hinder half: it was in two pieces (Plate VI., figs. 1, 2, v.). 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 07 
 
 The maxillo-palatine processes (mx.p.) ride over the palatines, and then, 
 hooking themselves backwards in a rounded form, bind against the sides of 
 the double vomer in its fore half. 
 
 Above, the lachrymals (Plate VI., fig. 5, Plate VII., /.) are seen to be 
 small bony hooks, with just a rudiment of a free supra-orbital process, and 
 a descending part that binds in between the descending arm of the nasal 
 and the antorbital cartilage. The frontals and parietals (/., p.,) fail at 
 present to fill in this swollen roof, thus leaving a large fontenelle (fo.). 
 The squamosals (sq.) -are very remarkable, and show us that we have here 
 a bird not cognate with the Anatidse — the aquatic branch of the bifurcated 
 gallo-anserine types — but a relation of the gulls and their allies. This is 
 at present inexplicable ; for, in the Cretaceous epoch, as we have seen,* the 
 divers and the gulls were as far apart as they are at this day. In the swan 
 (Plate IV, sq.) and in the fowl (op. cit, Plate LXXXIV, fig. 8, sq.) the 
 squamosal is a broad shield-shaped plate ; but here, in this diver, it is long 
 and falciform (Plate VII., sq.) — quite like that of the gull. This, we shall 
 soon show, is not the only thing in which these two kinds of birds agree. 
 Nevertheless, if Professor Huxley's Cecomorphaj is to contain both these 
 types, it must also be strong enough to bind together Marsh's Hesperornis 
 and his Ichthyornis. 
 
 The parasphenoid on the base (Plate VI., fig. 4, pa.s.) runs over the 
 vomer as a grooved and styloid bar, the trabecular balk lying in the 
 groove (see next stage, fig. 8, pa.s.) ; it has made a floor to the pituitary 
 space, has ossified the basisphenoidal region, has formed the anterior 
 tympanic recesses, and has grown into a pair of basi-temporal wings (b.t.) 
 that support the lagenee (au.). 
 
 Below, the four mandibular splints (fig. 6, d., sp., s.ag., ag.) are elastic 
 " withs" that are binding the struggling meckelian rods, which they will soon 
 overcome (see next stage, fig. 8). 
 
 The hyoid arch in this stage is composed of the columella (co.) above 
 and the two arches below ; the infrastapedeal at about this time, acquires 
 a small addition in the form of an arrested epi-hyal tract ; this, in 
 
 * Transactions, Linnean Society, New Series, Zoology, vol. i., Plates XXVI. -XXVII. 
 
 [9*] 
 
68 Cunningham Memoirs. 
 
 the adult, is the small tape of cartilage that lies upon the basi-temporal 
 plate, at the lower edge of the membrana tympani. The rest of the hyoid 
 (fig. 7) has not altered much, except in size, since the last stage (fig. 3) ; 
 yet the cerato-hyals {c.hy.) are becoming fused to form a basal piece 
 in front. 
 
 Stage 3. — Skull of Embryo o/Uria troile, nearly Ripe. 
 
 A vertically longitudinal section of the skull, at this stage (Plate VI., 
 fig. 8), shows that the hind brain only lies in that part of the floor which is 
 actually basal, and that this is only one-sixth of the length of the head. 
 But the oblique basi-cranial line (from the occipital foramen to the fore end 
 of the frontal cavity for the hemispheres) is half that length ; the brain is 
 a curved bulb, with its narrow part at the top and in front. The sudden 
 lessening of the bulb at the middle of the hemispheres removes the necessity 
 for any special orbito-sphenoids beneath it ; but it causes a remarkable 
 thrust, outwards, of the huge alisphenoids (als.), which are almost transversely 
 placed, and form the back wall of the large orbits, which closely approxi- 
 mate right and left of the interorbital wall. This tilting of the brain is 
 combined also with that of the auditory capsules, for these lie back so as to 
 form an acute angle with the basis cranii. But the shortness of the hinder 
 cranial floor is nothing new ; where that floor is long, as in Selachii and 
 Amphibia, the fore half is not axial ; the axis, or notochord, always ends 
 behind the pituitary involution. Here, in the bird, it only runs up into the 
 post-clinoid wall (p.cl), and then retreats,* so as to become the axis of the 
 only part that can be shown to be homologous with a vertebral centrum 
 or with centra. In the chick f the notochord becomes sub-moniliform ; and, 
 in the last of the three enlargements, the basi-occipital (b.o.) arises. Thus, 
 the specialization of the neural axis is correlated with a specialization of 
 the skeletal part that contains it ;% in Selachians this moniliform condition 
 
 * Soe Fowl's Skull, Plate LXXXI., figs. 2-4, nc. 
 
 f Soe Fowl's Skull, Plate LXXXIL, fig. 3, nc. 
 
 \ Transactions, Zoological Society, vol. x., Plates XXXV. and LX., nc. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 69 
 
 of the cranial end of the notochord is very remarkable, and shows how 
 indefinite the boundary is between the cranium and the spine in those 
 types.* 
 
 Whatever may be the nature of the pro-chorda! tracts of the primitive 
 cranium, they are responsible for a very large part of the cephalic endo- 
 skeleton ; in this case for five-sixths of its length. The optic nerves (ii.) 
 pass directly over the low hindpart of the gi*eat partition wall, at a short 
 distance in front of the foramen ovale (v.), which is a large round notch, 
 at present, between the auditory capsule and the wide alisphenoid. 
 Between those two nerves the sixth, fourth, and third nerves escape into the 
 orbit, whilst the seventh and eighth (vii., viii.) have their passages in 
 the fundus of a pit in the auditory capsule — the " meatus auditorius 
 internus." Between the capsule and the occipital arch the glosso- 
 pharyngeal and vagus (x.) escape, and the hypoglossal (xii. ) through the 
 ex-occipital. Rising almost vertically, with the alisphenoid right and left 
 of it, the wall at its oblique postero-superior corner is slightly two-lipped ; 
 these lips are the feeble orbito-sphenoid (o.s.). In front of this part the first 
 nerve (i.) runs right and left of the wall-top, grooving it. The olfactory 
 crus is simple, and supplies a very simple nasal labyrinth. In front of 
 the bony sella turcica (py.) the great trabecular balk is seen to form a 
 thick base to the wall. Above in the olfactory region the aliethmoidal 
 lamina3 grow out from its top ; the partition and these alse chondrify 
 together, and the nasal capsule has lost its independence in these high types. 
 A little further forwards the alas are called aliseptal (Plate VII., al.sp.), and 
 give rise to the coiled inferior turbinal ; still further forwards they are 
 called the alinasals (al.n.), being the valvular folds that surround the 
 external nostril (c.n.). The great partition, once a continuous tract as in the 
 adult Ratitse, has now a large, oblique, pyriform fenestra between the eyes, 
 and, in front of the true olfactory region, a large semi-circular notch (Plate 
 VI., fig. 8, c.f.c). Behind that notch the wall is triple ; in front of it it is 
 single, for the trabeculse cranii only reach thus far, and the rest is formed 
 
 * See Dr. Emil Rosenberg's excellent memoir, " Untersuclmng'en iiber die Occipitalregion des 
 Cranium und den proximalen Theil der "Wirbelsaule einiger Selachier." Dorpat, 1884. 
 
70 Cunningham Memoirs. 
 
 of the azygous intertrabecula. Here we see Nature dissecting her own 
 work ! The parts that had. become fused together are separating once more. 
 Not only is the intertrabecula separated from the ascending wall under this 
 great cranio-facial notch or cleft, but it is, also, under the septum nasi (s.n.). 
 That fore part of the general wall is of slight vertical extent in front, and 
 thus the two nostrils communicate — a common thing in birds thus to have 
 their nostrils open through. The intertrabecula, having served its purpose, 
 is now ready to vanish away ; in the old bird it has been absorbed— all but 
 the part which helped the paired trabecular to form that part of the balk 
 which is behind the hinge-notch. That notch has a thick, but lessening, 
 isthmus above it ; in front of that, the orbito-nasal branch of the fifth nerve 
 supplies the part; behind it, the olfactory nerve is distributed to the 
 slightly folded mucous membrane. Behind the notch, a little higher, there 
 is a bony plate as large as that notch ; this is the perpendicular ethmoid, or 
 mesethmoid process. The centre of the gently-swelling alisphenoid (al.s.) 
 is ossified ; the pituitary region has its borrowed basisphenoidal bony 
 tract (b.s.); the occipital arch is now in four centres — the supraoccipital 
 (s.o.), once double; the exoccipital (e.o.); and the oblong basioccipital(£.o.). 
 In front of the exoccipitals a small lanceolate opisthotic (»•/>•) is seen ; and a 
 large, squarish bone — the prootic {pro.) — is formed round the holes for the 
 facial and auditory nerves (vii., viii.). Between the side of the supra- 
 occipital and the large arch of the anterior semicircular canal (a.s.c.) there 
 is a semicircular space fitted only with membrane ; this is the lateral 
 occipital fontanelle which characterizes the skull in so many water and 
 wading birds, not excepting the Anatida?, which are so unrelated to 
 the rest.* 
 
 The articular («>-.) is enlarging, but I do not yet see the separate 
 endosteal centre in the articular enlargement of the mandible; the outer centre 
 appears some weeks before the inner ; it is some years before the latter 
 appears in the green turtle ( Chelone viridis); and its ectosteal articulare might 
 
 * The final purpose of these windows in the back of the head, in these birds, which are made 
 and then filled-up, as though they had been taxed, is not possible to conceive. The middle 
 occipital fontanelle, in owls and pigeons, is a mere economy of stuff. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 71 
 
 easily be mistaken for a mere parosteal splint by a young and incautious 
 morphologist. 
 
 The ectocranium at this stage is seen as an admirable supplemental 
 growth of bony scales over and around the primordial skull and face. The 
 imbrication of these "natural selections" from the inner face of ancient 
 ganoid scales, notwithstanding the extreme degree of specialization that all 
 these parts have undergone, is still as visible as that of the armour of any 
 ancient type of vertebrate. And yet, almost all these superficial bones have 
 their names from human anatomy, and a beginner can see the maxillary, 
 inter-maxillaries, nasals, frontals, parietals, squamosals, vomer, &c. (Plate 
 VI., fig. 8, mz.,p%., n.,f.,p., sq., v.). 
 
 Archaic parts, however, not seen in our own skull, are seen here, namely, 
 the rostral basitemporal parts of the ancient parasphenoid Qtra.s., b.t.) ; and 
 on the mandible all the reptilian splints except the coronoid (which also is 
 present in the arboreal birds, but not in these and many other Precoces). 
 But the dentary (d.), the splenial (sp.), the supra-angulare (s. ag.), and the 
 angulare {ag.) are well developed here, but little altered from what is seen 
 in ganoid fishes. 
 
 From the time of hatching to the first birthday of the bird, in one year 
 nearly every trace of the old landmarks are removed ; only in the specifically 
 ornithic jaws and palate are the elements at all kept apart. About half of 
 these are required in this most mobile apparatus. 
 
 At this point, my work is supplemented by Dr. R. W. Shufeldt's valuable 
 Papers, especially in that which treats of the skull of the adult guillemot.* 
 In one or two points as to the ossification seen in the skull of the adult 
 Alcidae, my valued fellow-worker has not quite caught my meaning in 
 certain of my memoirs on this subject. 
 
 In his earlier Paper on Alca in which the skeleton of Alca tor da is 
 described, f Dr. Shufeldt mentions a little bone attached to the lachrymal, 
 and which he supposes is the one called by me " os uncinatum " in my Paper 
 in the Encyclopaedia Britannica, vol. 9, art. Birds, p. 714. The bone 
 
 * Jour, of Anat. and Phys., vol. xxiii. (vol. iii. n. s.), pp. 166-171, Plate VII. 
 \ Ibid., vol. xxiii., p. 8, Plate I. 
 
72 Cunningham Memoirs. 
 
 referred to is, however, merely a limited ossification which takes place in 
 the hind part of the coiled inferior turbinal. This bone in my specimens 
 is an elegant open ring, the bony deposit having affected the whole coil to 
 a short extent; it is formed in front of the pars plana, where these two 
 parts are confluent.* But the true remnant of the os uncinatum is formed 
 in the intero-external angle of the pars plana (Plate VII., p.p., Plate VI., 
 fig. 4, p.p.), which is the homologue of the ethmo-palatine of the frog.")" 
 Besides the special middle turbinal centre which ossifies nearly all the 
 pars plana of these birds, there is formed in the adult a small milioline bone 
 in the angle just where the lachrymal ends below. There are two such 
 nuclei on the right side, some on the left in one of my specimens of the skull 
 of Uria troile, and one in the rest of my Alcido?,, namely, Alca torda and 
 Fratcrcula arctum. In gulls of the first year this angle remains unossified ; 
 but in old specimens it becomes a distinct os uncinatum, almost as well 
 developed as in the albatross. In an old Larus argcntatus it is triangular, 
 and the lower and longer side which is notched, is two millims. in extent. 
 In an old laughing-gull ( Gavia ridibunda) it is a wedge-shaped bone, 1 75 
 millims. long, and 1 millim. wide above. The ossified ends of the inferior 
 turbinate are very distinct and elegant in all my specimens of Alcidas ; and 
 they have the same development in Alca impennis, as my friend Frederic 
 A. Lucas has shown me. In a letter to me, dated January 22nd, 1888, he 
 gives some descriptions and careful drawings of these parts, and also of 
 another important and much larger osseous centre. This larger bone is 
 the ossification of the thick isthmus of cartilage shown in my third stage 
 in Uria troile (Plate 6, fig. 8, c.f.e.). That isthmus remains, for the segmen- 
 tation of the wall is not perfect, and the septumnasi (s.n.) in front of it is 
 arrested. This fore-wall is feeble in the adult of these Alcidas. This part 
 is broad and carinate ; the perpendicular ethmoid (p.e.) stops short at the 
 point it has reached antero-superiorly in my third stage ; and the roof 
 and keel in front of it is ossified as a separate thick wedge of bone. 
 This is seen in Alca impennis, A. torda, Uria troile, and Fratcrcula arctum, and 
 
 * Sec Fowl's Skull, Plate 86, figs. 6 and 8, pp. 1-16. 
 
 f See my Paper ou "Eemnants and Vestiges," Proc. Roy. Soc, vol. 43, Febr. 23, 1888, 
 pp. 400, 401. 
 
Me. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 73 
 
 is mentioned by Dr. Shufeldt in his description of the skull of Uria (op. cit., 
 p. 170) as existing both in that bird and in Alca. In old species of Uria 
 troile I find it 9 millims. wide behind, and 9 niillims. long ; and in front of 
 these is another bone like it, but only one-fourth the size. In an old 
 Gavia ridibunda there is a similar septal bone behind ; then a small nucleus ; 
 in front, the whole top of the septumnasi is ossified, and has coalesced 
 with the nasal processes of the premaxillaries. This septal ossification, 
 generally in one piece, is found in many of the Grallse and Palmipeds, to 
 say nothing of arboreal types. I find the main or hinder piece in 
 Podlceps minor, Rallus aquaticus, Porplujrio poltocephalus, Ardea cinerea, and 
 in Nycticorax. 
 
 The basi-pterygoids are absorbed in the adult ;* but the pterygoids 
 retain a little ingrowth towards the place where they existed in the 
 embryo. For the rest the reader is referred to Shufeldt's excellent figures 
 and descriptions. 
 
 I have purposely referred to the structure of other types of water-birds 
 and of their grallatorial relatives. Guided by the skull alone, we might 
 tie into one taxonomic bundle many a family of these birds : that is a clear 
 fact, and most important in ontological research. But it is a misleading 
 thing to do this in ornithology ; — a gull is one thing, a guillemot is 
 another, and a plover is diverse from both. Let us keep our evolutional 
 speculations apart from our taxonomic work: "there is no need of such 
 varieties " in that field of Science. 
 
 The Vertebral Chain and Bibs in Uria troile. 
 1st, 2nd, and 3rd Stages ; and 4th, or Adult. 
 
 It will be convenient to describe these stages together for the sake of 
 the mutual light shed by them. The vertebral formula in this type is 
 as follows : — 
 
 C. 15 (two or three ribs free); D. 7; D. S. 2 (second rib im- 
 perfect); L. S. 3 ; S. 4 ; U. S. 5 (riblet on first of these fused); 
 Cd. 10 + 3 : Total 49. 
 
 * See in Alca tarda, Shufeldt, op. cit., Plate I. 
 
 ROYA1 IRISH ACADEMT. CUNNINGHAM MEM01BS, NO. VI. [10] 
 
74 Cunningham Memoirs. 
 
 In the first, stage (Plate VIII. , fig. 1) there are only twelve vertebrae 
 between the hip-plates instead of fourteen : this is the ornithoscelidan 
 stage. In the second stage there are three distally articulated ribs on the 
 left side, at the end of the cervical region (Plate VII., c.r.) : the first of 
 these becomes fused in the adult. 
 
 It is worthy of remark that these birds, which feed on " small fishes and 
 Crustacea,"* should have a very strong neck with short vertebrae that have 
 strongly marked processes, whilst the heron, which, as a rule, deals w r ith 
 large prey, should have long, smooth, slender cervical vertebrae. I suppose 
 it is due to the more hurried manner in which they feed. The meditative 
 heron, when the necessity is laid upon him, suddenly — swift as an arrow — 
 seizes his prey. As compared with the Anatida? of the same size, the 
 e-uillemot has fewer cervicals, and each bone is shorter ; more dorsals — 
 seven instead of five ; fewer dorso-sacrals and uro-sacrals ; and a rather 
 longer, but feebler, caudal series. The spines, both upper and under, are 
 strong; the riblets are well developed, but do not exist on the atlas. On 
 the left side the last three, on the right the last two, are free. In the second 
 stage (Plate VII.), in the pre-sacrals, ossification has taken place in the 
 centra, neural arches, and riblets ; these latter are losing their distinctness. 
 The odontoid element, already united with the axis, the fore part of the 
 centrum of that joint, and the base of the atlas, are not yet ossified — one 
 centrum and two intercentra. Below, where the ribs are articulated, the 
 cervicals become rapidly approximated to the dorsals ; the spines become 
 square and crowded ; below, the spaces are bifurcated and dilated, right 
 and left. In the general sacrum, and in the caudal region, the centra are 
 acquiring an osseous deposit in the sheath of the notochord, but not as 
 yet the neural arches. 
 
 In Stage 1 the vertebrae are unossified ; in the pre-sacral region the 
 notochord, which had shown contractions at the joints, had become largest 
 there, and also was constricted so as to have two new swellings inside the 
 cartilaginous centrum. Behind the dorsal region (Plate VIII., fig. 1, nc.) 
 only two moniliform swellings are seen in each centrum, and these are lost 
 
 * Macgillivray, "Manual of Ornithology," 1842, p. 213. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 75 
 
 in the caudal region ; yet there the notochord has the amphibian character 
 of being largest at the intercentral spaces.* 
 
 Hence, this vertebral chain has evidently, like the rest of the organism, 
 been subjected to some dominating force that has fashioned it anew for 
 some further and higher ends in life, so that some unsightly creature, not 
 perhaps dissimilar to Siebold's gigantic salamander, or the eel-like Siren 
 lacertina, has been "clothed upon" not only with a warm, soft, feathery 
 and downy vestment, but has had its whole structure metamorphosed into 
 this "rich and strange" type. Nearly half a hundred links have been 
 developed in this cunningly wrought chain, where, perhaps, a hundred did 
 exist in the low quasi-larval ancestor. It is passing strange that a blind 
 force should produce such " new things in the earth." 
 
 The stunted condition of these post-dorsal vertebrae, the fore half 
 becoming fused and the hind half arrested, is in harmony with the rest of 
 the structure of this Pygopod ; nevertheless, had it been necessary, a 
 moderate amount of elongation would have made the eighteen vertebras 
 that are behind the true sacrals into the tail of a Saururous type as long 
 as the rest of the spine. The last four imperfect segments formed round 
 the notochord become the uropygial joint ; the nine in front of that keep 
 distinct ; their transverse processes (diapophyses) gradually decrease 
 to the end. 
 
 In this first stage the ribs on the first dorso-sacral are developed — are 
 almost complete below ; but on the second they are in three pieces, the 
 proximal (Plate VIII., fig. 1, s.r.) being a very small bar — simply a rudiment 
 of the capitulum and tuberculum. On the first uro-sacral there is an 
 attempt at the formation of a distinct rib bar. Hence, this part of the axis 
 is seen to be less perfectly developed than in the Anatidse. 
 
 Before hatching, in my third stage (Plate VIII., figs. 2, 3), the whole of 
 the general sacral series is enclosed between the ilia ; and the centra, but 
 not the neural arches, except in the first dorso-sacral, are ossifying. These 
 bony patches, formed, at first, round the notochord, are transversely oval : 
 the widest are in the swollen proper sacral region. These tracts are formed 
 
 * See Proceedings, Koyal Society, 1888, p. 466; and Foster and Balfour's "Elements of 
 Embryology, 1874," p. 157. 
 
 [10*] 
 
76 Cunningham Memoirs. 
 
 as far back as to the last four imperfect segments. Under the largest of 
 these, and under all the rest of the free caudals, there is, at the fore edge 
 of each centrum, a small milioline intercentrum ; above (fig. 3), four 
 vertebrae have a spine, that on the fourth being the smallest. The last 
 lumbo-sacral and those of the four proper sacrals are mere round belts; 
 then a small tubercular spine reappears, and is hardly lost on the last of the 
 four uropygial segments. That the cervicals in the adult are short is seen 
 by the following measurements: — The centrum of the eighth, or longest 
 of this chain, is 11 millims. long, the whole length of the vertebrae, with its 
 oblique processes, being 16 millims., and the width over the prezygapophysis 
 14 millims. The spines are well developed ; the four next behind the atlas 
 have upper and lower spines ; the tenth has a large lower spine ; then this 
 decreases, and there are three such outgrowths on the fourteenth. On the 
 fifteenth, or last cervical, and on the first two dorsals, the lower spine is 
 double, and dilated transversely, as in the loon (Colymbus), and another 
 fish-eating bird not related, the kingfisher (Alccdo ispida). The other five 
 dorsals — the first dorso-sacrals — have long simple spines, pedate below, 
 sloping from before backwards ; these spurs are like those of the grebes 
 (Podiceps), but are not so long. In this point the guillemot is intermediate 
 between the loon and the grebe, as Hesperornis is in its general structure. 
 
 The upper spine reappears in the last three cervicals. Thus, the last 
 of these, the seven dorsals and the two dorso-sacrals, form a gently arched 
 series of square spines, closely fitting— that is, with only a small tract of 
 elastic ligament between them, and tied together by fine bony tendons. 
 The dorsals, one with another, and the last of these with the first dorso- 
 sacral, are united by opisthocoelous joints, that have paired overlapping 
 processes, such as I have described in the oil bird.* All the cervicals, even 
 the last or fifth in its junction with the first dorsal, are heteroccelous, or 
 cylindroidal. The caudals are feebly amphiccelous, and have no joint 
 cavity. 
 
 In the guillemot the atlas has no rib bar enclosing the vertebral artery, 
 as in the duck and its congeners. It has one, however, on the axis, which 
 
 * Steatornis, Proceedings Zoological Society, 1889, Plate XVIII., p. 174. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 77 
 
 is not present in birds generally ; these riblets are developed into a long 
 style on the 3rd, 4th, and 5th, and these become short, and the retral part 
 is lost. The free rib on the 14th is 8 millims. long; that on the loth is 
 almost as long as that on the first dorsal, and it has an ossified uncinate 
 cartilage (see Plate VII.) ; these parts are long, and are present also on all 
 the seven dorsals ; thus there are eight pairs of them; they do not become 
 fused with the ribs. The ribs are extremely long, slender, and sinuous in 
 form, and are articulated to equally delicate sternal ribs at an acute angle. 
 The first forms, when at rest, a right angle merely; this is seen in an exagge- 
 rated form in the embryo (Plate VII.). Of course they are somewhat opened 
 out in inspiration. The last dorsal rib in Uria troile is 95 millims. long, its 
 sternal piece 81 "5 millims., a little more than half the length of the same 
 parts in Alca impennis.* The cinctures formed by the first dorso-sacral rib 
 just fall short below ; that of the second dorso-sacral is in three pieces on 
 each side. Above, a delicate bridge of bone is ankylosed to the vertebra 
 at both ends ; below a distal piece appears, 40 millims. long, attached to a 
 sternal piece, 50 millims. long ; the average breadth of these needles of bone 
 is - 75 millims. Sitting up, in full dress, these birds have a bulky look ; but 
 they are much more compressed than the duck or the penguin ; and their 
 trunk is not only very long for a bird, but also very deep. 
 
 In the loon ( Colymbus septentrionalis), and in the great diver (C. glacialis), 
 as also in the grebes (Podiceps), the body is very flat or dejn'essed, 
 strikingly so; compare Alca impennis [op. cit.), and Brandt's figures of the 
 skeleton of the loon {Eudyptcs {Colymbus) septentrionalis), and of Podiceps 
 auriius.f Besides, in these latter birds the ribs are much shorter and 
 stronger than in the Alcidse. 
 
 Altogether, in comyjaring these water-birds, each family seems to me to 
 be isolated, and they are probably much less nearly related to each other 
 than they seem to be, the similar adaptive modifications giving them a 
 misleading isomorphism. 
 
 In my second stage (Plate VII.) the ribs are accpiiring a long ectosteal 
 
 * Owen, Transactions Zoological Society, vol. v., Plate LI. 
 f " Zur Osteologie der VSgel," 1837, Plates XVI. and XIV. 
 
78 Cunningham Memoirs. 
 
 sheath, the sternal ribs (s.r.) are not yet ossified; their ossification takes 
 place in the same manner as in the vertebral ribs. 
 
 It is evident that sometimes the last cervical rib may join the sternum 
 by a sternal piece, although as a rule in Uria troile, Alea impennis, and Aha 
 torda, there are only seven pairs of sternal ribs. This additional sternal 
 exists in my third stage,* although there are only seven in the first stage 
 (ibid., fig. 10), and in the second stage also (Plate VII. of this memoir). 
 
 Also, in the same figure of the thorax of the third stage, the uncinate 
 cartilages (c.a.) are seen to have an adze-shaped dilatation above, when they 
 are fully formed. Even this undergoes change, and the enlargement is 
 much less evident in the adult. "With regard to the number of perfect 
 cinctures in the thorax in all Dr. Shufeldt's exquisite figures, f there is only 
 one with eight perfect sternal ribs, and this is on both sides (Plate III., 
 fig. 18, and Plate IV., fig. 20, p. 23). My specimen has only seven on each 
 side ; and some of the small forms of Alcidse figured by Dr. Shufeldt (op. 
 cit., Part III., pp. 400-558) are shown as having only six. 
 
 The Sternum and Shoulder-girdle of Uria troile, Embryos and Adult. 
 
 My dissection and drawings of the sternum of the first stage made long 
 ago (op. cit., Plate XVII. , figs. 10, 11) show that the metasternum is small 
 at first ; at that time it is no longer than the proper costal tract ; in the adult 
 it is three times as long (see Shufeldt). Why in these birds, which have 
 a tendency to abort the wing into a mere paddle, and in Tinamous 
 which have short wings that they have scarcely the sense to use, the meta- 
 sternum should be so extremely long, whilst in gulls, cormorants, the tropic 
 bird (Phaeton), and in the frigate bird (Tachypetes), it should be so short, 
 is to me, not at present engaged in myology, an anomalous fact. The 
 mechanism of flight in all these birds should be studied in reference to this ; 
 for the metasternum is, like the sternal keel, a thoroughly avian structure. 
 In Mammals it is a very feeble structure ; and in its earlier appearance in 
 Reptiles (Stellio, Crocodilus, op. cit., Plate XL, figs. 1, 2, 7, and 8) it is 
 
 * See " Shoulder-girdle and Sternum," Plate XVII., fig. 14. 
 t Jour, of Anat. and Phys., vol. xxiii. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 79 
 
 scarcely stronger than a rib. The common granular plate in which the rib, 
 at first, ends below, soon chondrifies, and then the right and left moieties 
 meet, unite together, form a keel, and become segmented from the lower 
 costal segments, or sternal ribs (op. cit., Plate XV., fig. 1). 
 
 In my first stage all this is complete, the structural relations are perfect ; 
 but the relative proportion of the regions undergoes much after-change. 
 
 In the second stage (Plate VII.) the rapidly growing embryo has its 
 sternum quite similar to that of the adult, and the metasternum is already 
 twice as long as the costal edge. The pre-costal process (p.cp.) has room 
 on it for two more sternal ribs, which might have grown down from the 
 neck. The rostrum, a special avian outgrowth,* and not a further sternal 
 rudiment, is already formed as a semicircular figure-head, separated 
 from the sharply-produced keel (st.k.) by an almost regular semicircular 
 notch. From that point to the flat, thin, keelless hind-part of the middle 
 metasternal process, the outline of the keel forms a large part of a quad- 
 rant. This convexity of outline is also seen in the body of the sternum, 
 which at this time bellies downwards, the thoracico-abdominal cavity being 
 pregnant with the copious viscera, and a huge mass of still unused food- 
 yolk. The lateral metasternals (m.st.) are separated by a round notch 
 from the middle plate, and are only half as long as its keelless part, behind 
 the fore end of the notch. 
 
 In the third stage (op. cit., Plate XVII., fig. 14) the sternum is rapidly 
 approaching the adult form, which is well illustrated in Miss Beatrice 
 Lindsay's Paper (op. cit., p. 690, fig. 1), and still better in Dr. Shufeldt's 
 4th part (p. 538, fig. 1, and p. 546, fig. 4). The sternum straightens 
 out very much, and the line of junction of the keel and body 
 becomes sinuous, for it rises in the middle of the metasteimum. The 
 keel projects its angle in front of the large deep rostrum, and ends 
 behind in a thickened edge, 3 millims. wide ; beyond this about 7 
 or 8 millims. of the rounded end is unossified. The rostrum comes 
 up well between the coracoid grooves. The whole bone is very evenly 
 oblong ; it measures 37 millims. across the tips of the pre-costal 
 
 * Lindsay, Proceedings Zoological Society, 1865, p. 707. 
 
80 Cunningham Memoirs. 
 
 processes, and also across the outer metasternal processes, and only 31 
 millims. behind the last sternal rib. The whole median length is 123 
 millims. — nearly four times the average width ; and the keel is 128 millims. 
 long, measured in a straight line above its gently curved lower limbate 
 edge : its greatest depth is 30 millims. The depth of the notches in the 
 metasternum varies in individuals ; in my specimen of an adult they reach 
 half-way to the last sternal rib, and the lateral bars are 20 millims. long and 
 4 millims. wide. The gently descending series of the seven transverse 
 costal condyles look equally outwards and upwards ; thus the costal 
 cinctures swell out above the sternum. 
 
 I have noted down this great length and narrowness in the guillemot, 
 both for comparison with the short-breasted gulls,* which come so near the 
 Limicolas in this respect, f and also with the loons.J In the gulls the 
 sternum is both narrow and short ; in the loons it is as long, or nearly so, 
 as in the Alcidae, but much wider. These long sterna had their counterpart 
 in an arrested condition due to the abortion of the wings in the extinct 
 Hesperornis.§ In that bird the sternum, and also the furcula, are almost 
 exactly like those of my third stage of the guillemot.|| 
 
 Even the skull itself is of less value to the ornithologist than 
 the sternum ; it will be seen at once that this statement is somewhat 
 remarkable as coming from one so partial to the skull. And yet, 
 notwithstanding this, the Alcidae, in several important respects, come 
 nearer to the Laridae than to the other divers (Urinator, Eudyptes, or 
 Colymbus), for these latter forms, with their quasi-ancestor Hesperornis, 
 and the grebes, have all their pre-sacrals cylindroidal.^f 
 
 The ossification of the sternum in the Alcidae is by a very generalized 
 sort of endostosis, the lophosternum having a very short independence of the 
 
 * Shufeldt, Part i., Plate IV., fig. 2. j ^id., figs. 22 and 23. 
 
 \ Shufeldt, Part ii., Plate VIII., fig. 7 ; and Brandt, op. tit., Plate XVI. 
 
 § Marsh, op. cit., Plate VII. 
 
 || Shoulder-girdle and Sternum, Plate XVII., figs. 10, 11, and 13. 
 
 ^f The nomenclature of these birds is very confusing. E. Nitzseh (Pterylography, Ray Soc, 
 1867, p. 152, Plate X., figs. 10, 11, and 12) calls the grebes Colymbus, and the loons Eudyptes ; 
 whilst Macgillivray (Manual, 1842, pp. 200-206) calls the grebes Podiceps, and the loons 
 
Me. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 8 1 
 
 pleurostea. The shoulder-girdle of the g-uillemot* has a falciform scapula 
 (so.) nearly twice as long as the coracoid (or.). In the first stage (op. cit.) 
 the axes of these two bars are coincident ; they are ossifying separately, 
 but are only half free from each other at the shoulder-joint. On the fore 
 part of the head of the coracoid there is a small continuous remnant of the 
 precoracoid, which becomes the clavicular process. In the third stage 
 (op. cit.) there is a separate nucleus of cartilage — an external precoracoidal 
 remnant — -which becomes part of the ramus of the f urcula, after undergoing 
 endostosis ; and it forms a shelf, on which the large f or wardly- curved head 
 of the coracoid rests ; that is a flat synovial joint. This structure can be 
 seen even on the inner aspect, f The shaft of the coracoid is moderately 
 slender, and the epicoracoid below has a dilated hook at its hinder angle.J 
 The clavicular rami are largely curved forwards above, and the Avhole 
 from a side view, with the crescentic interclavicle, forms a rough semi- 
 circle; but the rami are not so evenly curved as in the loons, § which 
 have also a smaller interclavicle. In the loon, in the first stage of Uria,|| 
 and in Hesperornis,^| each ramus is much dilated above ; and this dilatation 
 is formed in a mass of granular tissue, which is almost cartilaginous, and 
 belongs to the acromial or meso-scapular region. The rami of the furcula, 
 like the little bone at their junction (the interclavicle), are parostoses. 
 This median part was not seen by Marsh in Hesperornis.** 
 
 Anyone who will compare together the figures given in the thirteenth 
 Plate of my work on these parts will see at a glance that the reptile has 
 the raw materials out of which the bird's shoulder-girdle might have been 
 made. 
 
 Colynibus ; whilst Brandt (op. cit.) calls the loons Eudyptes, and the grebes Podiceps. To mend 
 the matter, the best and latest authorities, the ornithologists of the American Union (The Code of 
 Nomenclature and Check-List of North American Birds: New York, 1886), have for the grebes the 
 generic terms iEehmopliorus, Colymbus, and Podilynibus ; and for the loons Urinator (pp. 73-76). 
 
 * Op. cit., Plate XVII. , figs. 10-4 ; and Plate VII. of the present Paper. 
 
 f Shufeldt, op. cit., Part iii., p. 556, fig. 8. J Ibid, 
 
 § Brandt, Plate XVI.; and Shufeldt, Part ii., Plate IX., figs. 2 and 13. 
 
 || Op. cit., Plate XVII., fig. 13. 
 
 <i Marsh, op. cit., Plate VI., fig. 3. 
 
 ** Op. cit., Plate VII., fig. 8. 
 
 BOYAI, HUSH ACADEMY CUNNINGHAM MEMOIRS, NO. VI. [11] 
 
82 Cunningham Memoirs. 
 
 The Wings of Alca torda and Uria troile in Embryos and the Adult. 
 
 The wing in Alca torda one-third ripe, and therefore answering to my 
 first stage in the guillemot, is considerably advanced in growth (Plate IX., 
 figs. 1 and 2); it answers very nearly to my third stage in the duck 
 (Plate I., fig. 6). The main parts are already well formed, and the larger 
 rods have their ectosteal sheath ; but the parts that form the strangely 
 modified carpus are still cartilaginous. 
 
 The radiale and ulnare (re., ue.) are large and normal, and the distal 
 carpals (d.c. 1 d.c." d.c. 3 ) are well formed. The first of these is on the inner 
 side (fig. 2, dc. 1 ); it is ear-shaped, and strives to reach its own short meta- 
 carpal (m.c. 1 ) which is fused with the great crescentic second metacarpal 
 (m.c. 2 ), as also is the oblong third distal carpal (d.c. 3 ). The great second 
 metacarpal is four times as long as the first, and one-fourth longer than the 
 third (m.c. 3 ), which is also very slender. The proximal phalanx of the large 
 index (dgr) is beginning to ossify ; all the rest are cartilaginous. The two 
 phalanges of the pollex are equal in size to the two distal ones of the 
 index ; the one distal or undivided phalanx of the third digit (dg. 3 ) is 
 two-thirds the length of the proximal phalanx of the pollex. 
 
 In the second stage Uria troile (Plate VII. and Plate VIII. , figs. 7 and 
 8) shows some new parts besides increase in size and development of two new 
 bony sheaths, one in the proximal phalanx of the pollex, and another in 
 the middle phalanx of the index. The distal phalanx of the pollex is now 
 very small, and the claw is dying out ; and that of the index is almost fused 
 with the middle piece. The displaced and greatly masked first distal 
 carpal (d.c.') has its base, on the ulnar side, dilated and fused with the parts 
 on which it lies : a little beyond it, inside the head of the third meta- 
 carpal (m.c. 3 ) there is an oval segment of cartilage half the size of the first 
 distal carpal ; that is the remnant of the fourth metacarpal (m.c.*). On the 
 ulnar, or hinder, side of the large proximal phalanx of the index — between 
 it and the lessened phalanx of the third digit (dg. 3 ) — there is a new lanceo- 
 late cartilage, which is already receiving bony deposit from the ectosteal 
 sheath of the large primary bar to which it is attached ; this is a proximal 
 
Me. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 83 
 
 secondary phalanx (dg. 2 '). Above, in the outer or extensor face of the 
 manus (Plate VIII., fig. 8, mc. 2/ ), there is a semi-lanceolate tract of car- 
 tilage outside the ectosteal sheath of the great second metacarpal (ni.c. 2 ) — a 
 secondary metacarpal ; a weak fork of the index. That attempt at bifurca- 
 tion of the great second ray of the hand is connected by a distinct but 
 slender isthmus with a fork of the great second distal carpal (d.c. 2 ). I 
 can find no teleological reasons for these multiplications or forkings of 
 the contracted and aborted manus of the bird.* 
 
 In Aha torda, also, the second stage (Plate IX., figs. 3, 4) is illustrated. 
 It shows the same parts as the similar embryo of the guillemot. In this 
 embryo the pollex and index have both kept their' distal joint distinct; and 
 in the third digit there is a very small grain of cartilage distinct from the 
 proximal part. The first distal carpal and the fourth metacarpal (figs. 3, 
 d.c. 1 , m.c. 4 ) are clearly seen ; and, on the outer side, the second distal carpal 
 has sent on a styloid fork, which is connected by a membranous isthmus 
 with the secondary second metacarpal (fig. 4, m.c. "-'). 
 
 In both Una troth and Aha torda, the third stage, or almost ripe 
 embryos, show a still further growth of the wing. In Uria (Plate IX., 
 fig. 7) the changes from Stage 2 are merely those of growth. In Alca 
 (Plate IX., figs. 5, 6) I have shown the parts on a larger scale ; in these we 
 see that the cartilages are becoming vascular, ready for ossification. The 
 great proximal carpals [re., tie.) show by their lobes that they represent 
 more than one normal nucleus ; and the distal carpals (d.c. 1 ''') are still suffi- 
 ciently distinct to illustrate their peculiar forms and relations. On the 
 fore edge of the first metacarpal (m.e. 1 ) there is a suspicion of a pre-pollex 
 
 * If anyone studying these parts does not see in them a repetition of what occurs in the fore 
 paddle of an Ichthyosaurus ; and if, looking at both, he is not irresistibly carried into ontological 
 speculation, there must be some weak spot in his mind. All minds are not so timid : whilst 
 writing the above I have received a very valuable Paper on this subject, by M. Alfred Tschan 
 ("Eecherches sur l'Extremite Anterieure des Oiseaux et des Reptiles." Geneva, 1889). Both 
 as to personal research and as to Bibliography, this Paper comes to me very opportunely, and I 
 am grateful for it. I cannot, however, quite see with M. Tschan as to the manus of birds ; he 
 would make the normal third ray to be the fourth digit — the third, in that case, being my inter- 
 calary post-index (p. 59). 
 
 [11*] 
 
84 Cunningham Memoirs. 
 
 in the peculiar form of the trochanter. The ventrally displaced first distal 
 carpal (d.c. 1 ) is attached by a large base to the second and third metacarpals ; 
 and, on the postero-internal face of the latter, the fourth metacarpal (me. 4 ) 
 is clearly seen as an oval milioline nucleus of solid cartilage. But these 
 unhatched Alcidae are not all that is needed for the interpretation of the 
 adult wing. Happily, however, through the kindness of Frederic A. Lucas, 
 Esq., of Washington, I am able to show the structure of the wing in a half- 
 grown bird — the smallest of the family, namely, Ciceronia pusilla* 
 
 In this relatively large bird of the first summer I found an explanation 
 of what is remarkable in the pollex (in many cases it is seen in the index 
 also) of water-birds — Alcida?, Procellariidse, and Phalacrocoracida?. 
 
 In the long manus of the smallest auk (Plate VIII., figs. 9—13) the 
 ossifications are, in this immature bird, nearly all distinct, and thus very 
 instructive. The distal carpals (figs. 9 and 12, d.c.\ (I.e.-, d.e:' J ) are bounded 
 by sutural lines that are just becoming obliterated, and the three meta- 
 carpals are not yet fused. There is no appearance of a distal joint in the 
 third digit (dg. 3 ), but those of the pollex and index (dg. 1 , dg. 2 ) are ossifying 
 as a separate endosteal patch. The latter have become fused with the 
 middle phalanx, as in Uria troile (fig. 7); the last phalanx in the pollex 
 keeps its distinctness, as in the large bird. The semi-lanceolate secondary 
 second metacarpal (m.e. 2 ') is getting some bony deposit from the main 
 shaft ; that of the proximal phalanx is completely fused with the main 
 piece, and is largely ossified. Another very distinct segment of cartilage 
 has appeared in the ulnar side of the proximal joint of the pollex, near its 
 distal end (dg. l ). This is a perfectly distinct semi-oval cartilage, which 
 is ossifying from its own proper endosteal centre, just as the secondary 
 metacarpal of the index does in passerine birds, when it is most perfectly 
 developed. The ungual phalanx of the pollex has a delicate claw upon it. 
 This post-pollex is accompanied with a post-index in these Alcidee and some 
 other Palmipeds ; for, in the adult Uria troile, Alea torda, and Fratercula 
 indiea, the same flange is seen in both of those digits (see in Uria troile, 
 Plate IX., figs. 11, dg. V, and fig. 12, dg. 2 1 ). 
 
 * Simorhynclius pusillus (see Check-List of North American Birds, p. 79). 
 
Mr. W. K. Pakker. — Morphology of the Duck and the Auk Tribes. 85 
 
 All the secondary parts, or feeble forks, of these digits or rays here 
 described, are on the ulnar side of the primary rays ; that, however, is not 
 an absolute rule, as many passerine birds have a pre-index nearly as large, 
 and quite as independent, as their large post-index ; and both these sup- 
 plementary rays are attached to the main metacarpal, the one on the front 
 or radial side being attached much further down than that on the ulnar 
 side. These unexpected complexities of the transformed fore-paw in birds 
 are being traced out in the whole class, and will be published in due time.* 
 
 I have one word more to say about these secondary forkings of the ra) T s 
 of the fore-limb. If they were merely adaptive enlargements for the sake 
 of the setting in of the quills, why did Nature create new cartilaginous 
 rays, ossify them autogenously, and then obliterate all signs of their 
 temporary independence ? Any slight extension of periosteal bone from 
 the normal rays would have sufficed to produce these flanges and inter- 
 osseous bridges. No expenditure of the morphological force was needed 
 for such after-touches as these. Thus the teleologist is quite at fault here : 
 there is no scent : another hound may cry upon the right track, but lie will 
 have to be one of the ontological breed. 
 
 Hip-girdle of Uria troile, Embryos and Adult. 
 
 This part of the skeleton, including the sacral vertebrae, is of great 
 interest; both the pelvis and the dorsal vertebrae are in accord; both 
 suggest a nearer relationship of the Alcidae to the gulls on one hand, and 
 to the penguins on the other, than to those important Pygopods, the 
 Colymbidse and Podicipitidae, that seem to be the true descendants of the 
 extinct Hesperornithidae. I shall return to this subject in describing the 
 pelvis of the adult. 
 
 * "With regard to secondary rays in the fore-paw of extinct reptiles, Dr. G. Baur (see my 
 reference to his views, Proceedings, Eoyal Society, 1888, p. 323) insists upon their presence 
 on the ulnar side, only, of the primary rays. Mentioning this to Professor H. G. Seeley, I 
 obtained from him a distinct denial of the truth of Dr. Baur's assertion. I must say that what 
 1 have seen in so many passerine birds makes me feel sure that they may occur- on both sides. 
 
86 Cunningham Memoirs. 
 
 In the first stage of Una troile the hip-plate (Plate VIII., fig. 1) is, as 
 to form, in the struthious condition ; the three main bars, or plates, are 
 distinct rays behind, the ischium (isc.) not having become fused with the 
 post-ilium (pt.i.). At this stage the hip-girdle is just in extreme contrast 
 with that of the adult loon (Colymbus septentrionalis), in which the post- 
 ilium is two and a-half times the length of the pre-ilium. In this embryo 
 of the guillemot the post-ilium is not two-thirds the length of the pre-ilium, 
 and, in the adult, is only three-fourths its length — exactly the same pro- 
 portion as in Eiuh/ptcs chrysocome* This pelvis (Plate VIII., fig. 1) has 
 dilated pre-ilia, and contracted post-ilia, "j" 
 
 Behind the rounded free ends of the pre-ilia the plates contract, and 
 then dilate to form the fore part of the acetabulum ; beyond which they 
 grow along the sides of the sacrum for some distance, and then diverge 
 and end in a pointed process, whose lower margin is notched. Below the 
 post-ilium the ischium (isc.) runs backwards as a broadening flap of car- 
 tilage, which also ends in a point at some distance behind the post-ilium. 
 The pubis (pi.) is less than half the breadth of the ischium; and it goes 
 still further back, so as to be almost twice the length of the post-ilium ; it 
 is terete, not flat, and ends in a point. Nearly the middle third of the 
 pubis is ossified ; the ilium is ossifying along its outer edge ; and the 
 ischium has a small bony patch over the proper obturator space. 
 
 Some curious changes are seen in the hip-plate in Stage 2 (Plate VII.). 
 The two moieties are strongly clamped upon the sacrum, and contract in 
 upon the caudal vertebrae also. The osseous centres are much enlarged, 
 and the iliac bone is now some distance behind the acetabulum ; the three 
 rays are all distinct behind. But the most remarkable change has taken 
 place in the pubis ; it is crumpled in exactly the same manner as the inter- 
 trabecular rostrum and the meckelian rods in the same stage (Plate VI., 
 figs. 4 and 0). This crumpling is apparently due to the faster growth of 
 
 * Morrison "Watson: "Challenger Reports" (Spheniscida), Zoology, vol. vii., Plate VII., 
 figs. 7 and 8. 
 
 f The figure is from an outspread preparation. This is corrected in Stage 2, Plate VII., and 
 in Stage 3, Plate VIII., figs. 2, 3. 
 
Mr. W . K. Parker. — Morphology of the Duck and the Auk Tribes. 87 
 
 this part as compared with the structure with which it is bound up ; in the 
 adult the pubis is very long. In Stage 3 (Plate VIII., figs. 2, 3) the 
 general growth has gone on, and one of the pubes — the left — has become 
 dilated at its end ; in the adult both are dilated, as in the Anaticlse. The 
 ilia coalesce with the sacrum, but leave a large groove open, right and left, 
 in the fore-part of the pelvis, above ; the post-ilia reach the third caudal 
 vertebra, so independent is the boundary between the uro-sacral and the 
 caudal region. The slender pubes keep free from the ischia ; they are 
 arched upwards, and the lower edge of the ischia is concave, parallel with 
 that arching. 
 
 If we compare the pelvis of one of these Alcidse with that of a gull and 
 of the plovers,* it is evident that the Alcine pelvis is but a contraction of 
 the Larine, as the latter is but that of a plover made narrower. But the 
 pelvis of the razor-bill and penguin are still more alike ; f whilst the pelvis 
 of ColymbusJ is seen at once to be a modern form of that of Hesperornis.§ 
 Also, let it be noted, that, whilst the Anatidee agree with the grebes, 
 loons, and Hesperornis, in having cylindroidal dorsal vertebrae, they also 
 agree in having the post-ilium much longer than the pre-ilium.j| 
 
 These are only a few of the difficulties that rise up to confuse the 
 classifier of the Palmipeds ; they are more than doubled when we bring in 
 the Procellariidas and the Pelecaniidse, using the latter term in its widest 
 sense. 
 
 Hind-limb in Uria troile ; Embryos and Adult. 
 
 In Stage 1 this part is still in its archaic or dinosaurian condition. 
 Most of the primary elements of the limb are uncombined, but they are 
 placed together ready for confluence (Plate 8, figs. 4, 5). The fibula has 
 retreated upwards; the tibia (t.) having drawn the nourishment out of it, 
 this latter rod has the upper part of the tarsus articulated with it. The 
 
 * See Shufeldt, op. cit., Part ii., Plates X. and XL 
 
 t Watson : op. cit. Plate VII., figs. 7, 8. % Brandt : op. cit., Plate XVI. 
 
 § Marsh : op. cit., Plates X. and XL 
 
 || See Plates III.-V. of the present Paper ; and Shufeldt, Proceedings, U. S. Nat, Mus., 
 vol. xi., pp. 225, 226, figs. 6-8. 
 
88 Cunningham Memoirs. 
 
 three proximal tarsals, tibiale, fibulare, and intermedium (tb., /be., i.) are 
 traceable, but arc not now distinct nuclei; the supero-anterior element, the 
 intermedium, is short, as in the common chick, not long, as in the goose 
 tribe and the Ratitse; it is an obliquely-placed diamond-shaped plate 
 attached below to the fibulare, and overlapping the outer part of the tibia 
 above. 
 
 Below these the single distal tarsal forms (d.t.) a sinuous cap to the 
 three developed metatarsals (m.t 2 '*) ; and behind and between the two 
 masses on the inner tibial side, there is a small nucleus answering 
 to the scaphoid or centrale (c), and a small elevation on the fibular 
 side of the distal tarsal and fourth metatarsal [d.t.,. m.t.*) ; this is all 
 that is left of the fifth metatarsal (m.t. 5 ). At the lower third of the second 
 metatarsal (m.t. 2 ) a small miliuline g-rain of cartilage is all that is left of the 
 first metatarsal (m.t. 1 ), and thus the outer and inner digits are suppressed. 
 The other three are normal, with their three, four, and five phalanges 
 (Plate VII.); but their metatarsals (m.t."'*) are distinct, and diverge so as 
 to produce a sprawling or reptilian foot ; more than the middle third of 
 these metatarsals is ossified. In Alca tarda at this stage (Plate IX., fig. 8) 
 the proximal tarsal mass is shown, and the separate tendon-bridge. In 
 Stage 2 (Plate VII., and Plate VIII., fig. 6) the parts are larger and more 
 ossified: the characteristic change is seen in the metatarsals (m.t. 2 '*) which 
 have been squeezed together, so to speak, closely faggoted into a single 
 shank, and flattened when they adhere to each other. In Stage 1 the third 
 was a little behind the other two ; it is the largest, and has the largest 
 head, which projects considerably behind the other. Above these rods 
 the distal tarsal has grown up a front to form the very avian intercondyloid 
 knob. The small oval intermedium (/.) is still markedly separate from the 
 fibulare or outer condyle. The centrale (<?.) is now merely a thickening 
 in the inner part of the growth of the general tendon-sheaths for the plantar 
 tendons. 
 
 In Stage 3 (Plate IX., figs. 9, 10) the common mass of the tibiale and 
 fibulare (tb.,jbc), and the tendon-bridge are still cartilaginous, and will be 
 for a good while to come ; but the intermedium is now ossified by ectostosis, 
 and overlaps the tibia antero-externally. The arrested first metatarsal (m.t. 1 ) 
 is still unossified. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 89 
 
 In the adult these parts are all ossified and ankylosed together ; even 
 the secondary tendon-bridge; the intermedium can be traced as a small 
 triangular projection above the inner condyle. Even in old Alcida?, the first 
 metatarsal is visible as a small, flatfish grain of bone. In Fratercula arctica 
 it is 1 millim. in diameter. 
 
 In the old guillemot ( Una troile) the patella is large and thick, 5 millims. 
 high, and the same in width. The cnemial ridges of the tibia are strong and 
 high, the fibula one-third shorter than the tibia, and the femur moderately 
 long and gently curved. The shank is only three-fourths the length of 
 the middle toe. The length of the toes is as follows : — Second, 35 millims. ; 
 third, 49 millims. ; fourth, 46 millims. 
 
 The position of the guillemot, somewhere between the loon and the 
 gull, may be illustrated by a comparison of the relative length of the three 
 main divisions of the hind-limb : — 
 
 Femur. 
 
 Tibio-tarsus. 
 
 Tarso-nietatarsus. 
 
 Larus argentatus, 59 millims. 
 
 Uria troile, 47 millims. 
 
 Coli/mbus septentrionales, 37 millims. 
 
 109 millims. 
 
 91 millims. 
 
 165 millims. 
 
 04 millims. 
 36 millims. 
 71 millims. 
 
 In each case the tibia has had about 5 millims. of its length added to it 
 by the proximal tarsal mass, whilst the cnemial process has added : in the 
 gull, 6 millims. ; in the guillemot, 7 millims. ; and in the loon, 42 millims. 
 Here we see that in the loon the femur is so short that the tibio-tarsus is 
 four and a-half times its length. The proportion in the gull is less than 
 twice ; and in the guillemot the femur is somewhat shorter relatively than 
 in the gull. 
 
 I do not wish to lay too much stress on these measurements ; I must 
 remark on the extreme modification of the hind-limbs and pelvis in the loon, 
 making it the isomorph of the seal (Phoca). But what is pertinent to the 
 subject is, that it is not a modern specialization; it is as "old as the 
 (Cretaceous) hills," and j)robably much older; for Hesperornis, that almost 
 
 EOYAL IEISH ACADEMY CUNNINGHAM MEMOIRS, NO. VI. 
 
 [12] 
 
90 Cunningham Memoirs. 
 
 wingless and toothed loon, must have existed long enough to abort his wings 
 and lose his sternal keel. 
 
 Summary. 
 («) The Anatidce and Alcidce considered from an ornithological standpoint 
 
 Continuing my observations on the relationship of these two widely 
 separated families of birds, I would reiterate the remarkable fact that the 
 Anatidre manifestly converge towards the gallinaceous group ; that they 
 have the struthious division of the Ratitse obliquely below them ; whilst 
 the Alcidae are related to a large and varied group of existing families, 
 but, in their ancestry, belong somewhere between those two extremely 
 dissimilar extinct families, the Hesperornithidre and the Ichthyornithidae. 
 The revelation made by the precious remains of those two ancient toothed 
 types throws a blight light on one side of these questions of origin and 
 relationship, but intensifies the darkness on the other side. The glare 
 makes some things appear darker than they were before those treasures 
 were unearthed. 
 
 The loss of teeth is evidently a comparatively modern specialization, as 
 compared with the general structure of the bird ; the Anatidas, however, 
 have had time, not only to lose their true teeth, but also to gain false 
 teeth, or horny imitations — succedanea — in their place. The Alcidae, 
 however, are no losers ; their shorter cultrate elastic beak is a most mobile 
 and strong pair of fish scissors, much more effective than the long, toothed 
 jaws of an Ichthyornis could have been. 
 
 Higher up in the class the gain has been exceedingly great : the house- 
 martin, the chaffinch, the long-tailed titmouse, and the tailor-bird owe the 
 possibility of their exquisite architectural skill to their toothless jaws. 
 But maxillary armature is but a small part of a vertebrated organism ; the 
 morphologist has much more to do than to study teeth. 
 
 Diagrams of "family trees" do not help us much; they are easy to 
 make ; the real difficulty lies in proving that they illustrate anything that 
 ever actually took place in Nature. 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 91 
 
 I am under the impression that penguins never possessed quills, and 
 that their adaptation to aquatic life, and their great power of diving, took 
 place much earlier in their ancestral history than in the case of the auks 
 and guillemots — birds that tend to become a sort of palsearctic penguin, 
 but never quite lose the marks of their former adaptation to a more terres- 
 trial life. I conceive of their ancestors in amphibious or limicolous birds ; 
 and I imagine the forefathers of gulls, plovers, rails — the auk tribe — as 
 being very much alike, and very nearly related. 
 
 I am the more led to this way of thinking by what is seen in those 
 remarkable Limicolse, the sheath-bills (Chionis), and also in their near 
 relatives Thinocorus and Attagis. These archaic neotropical plovers 
 (Liinicoke) are aberrant and almost extinct types. In the case of Chionis 
 alba the skull is extremely like that of the razor-bill (Alca torda) — so much 
 so that, if it had come to me as a fossil, nothing more being known of the 
 bird but the remains of its skull, I should unhesitatingly have put it 
 amongst the Alcidas. I have already referred to the pelvis of this genus, 
 and of the plovers and gulls, in describing that of Uria.* But the penguins, 
 with their extreme specialization as the highest form of divers, must, it 
 appears to me, have been penguins since the day they acquired their 
 peculiar mantle. They were amphibio-Dipnoans ; they became transformed 
 into what we now see — perchance they were somewhat clumsier at 
 first. 
 
 It is in the hind-quarters that the extinct ornithoscelidan reptiles 
 approach the bird in their organization ; in the penguin those parts are, 
 even in the adult, least modified from the condition seen in these reptiles. 
 Their spine, in the dorsal region, has the archaic opisthoccelian articula- 
 tions ; their skull is of a generalized form, a little more primitive than that 
 of a razor-bill ; and the appearance of the head in its feathers is much like 
 that of the large embryo of the guillemot (Plate IX., fig. 18). 
 
 All the penguins are alike in every tiling that is important ; j" of the 
 
 * See Shufeldt, op. cit., Part x., xi., for figures of the pelvis in Chionis minor. 
 f It is remarkable that the gigantic extant penguin (Palaseudyptcs — see Huxley, Proceedings, 
 Geological Society, 1859, pp. 670-676) should, like the great ostrich, have only two toes. 
 
 [12*1 
 
92 Cunningham Memoirs. 
 
 Alcidae only one, Aha impennis, became transformed into the likeness of a 
 penguin ; the specialization of the family has been imperfect, as compared 
 with the penguins, and, as I believe, took place later in time. 
 
 Returning to the duck tribe, and again referring to the fact that they 
 evidently come from a stock closely related to that from which the fowl- 
 tribe sprung, we must cither give up the doctrine of the evolution of all 
 these various types, in time, or make ourselves satisfied that some low, 
 unsightly amphibious fowl — a wader of some sort — gave rise to two tribes, 
 the Anatine and the Gallinaceous ; and was thus, at once, the ancestor of 
 the swan, on one hand, and of the peafowl on the other. This is enough 
 to stagger the faith of the most robust Darwinian ; but true faith laughs at 
 impossibilities — that is, at what seem to be such to our scant knowledge 
 and limited reason. 
 
 Without losing ourselves in the past, there is much in the present to 
 interest us. The two groups treated of in the present Paper are, for 
 ornithological purposes, very instructive, being so sharply defined from 
 each other, albeit they are both made up of forms that are adapted to 
 aquatic life. The Anatidre, which are more or less terrestrial also, are 
 mainly swimmers, and some of them, as the swans, are sailors. The 
 Alcidse are not more fit for land than the eared seals (Otarire); but they can 
 fly, and they can dive — are equally at home and at ease in the rarer or 
 the denser medium. For taxonoinic use the skeletal parts come in very 
 usefully ; Professor Huxley has shown us how to turn these parts to 
 account. 
 
 Now, these tw T o families are, in respect of their osteological structure, 
 sharply divided from each other : the points in which they agree are few r er 
 than those in which they disagree : — (a) The wdiole skeleton is much 
 stronger, and more pneumatic, in the Anaticke than in the Alcidas. 
 (b) The Anatidse are desmognathous and holorhinal ; they have permanent 
 anterior basiptcrygoids, an azygous vomer, massive basitemporals, pro- 
 duced posterior angular processes to their mandible, dilated jaws covered 
 with horny lamellae, cylindroidal dorsals, a furcula composed of clavicles 
 only, and the post-ilium much longer than the pre- ilium. The Alcidpe 
 are schizognathous and schizorhinal ; they have temporary middle basi- 
 
Mr. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 93 
 
 pterygoids, a double vomer, delicate basitemporals, arrested posterior 
 angular jjrocesses, contracted and cultrate jaws, opistlioccelous dorsals, a 
 considerable interclavicle in the furcula, and their post-ilium is much 
 shorter than their pre-ilium. Now, if the ornithologist will add these 
 differences to those which are familiar to him in the superficial structure of 
 these birds, they will greatly strengthen and enrich his taxonomy. Also, 
 looking on this picture and on that, he will be able to judge where these 
 two families should be set in the class, so that his grouping of the plumy 
 tribes may be as " goodly as the tents of Jacob." 
 
 We can now leave the fowler, and turn to that other labourer, who 
 works with a spado and a pickaxe : the palaeontologist is asking what all 
 this modification of a reptilian type means, and how it bears on his 
 special work. 
 
 (b) The Anatida and Alcidce considered from an ontological standpoint. 
 
 If it has become clear that the birds are not sharply separated from 
 the reptiles, it has also become equally clear that the reptiles are not 
 sharply separated from the amphibians. 
 
 As to its hind-rpiartcrs,* the humming-bird is but a Dinosaurian — a 
 sort of Iguanodon, intensely ossified, albeit the latter may be as large as a 
 whale, and the former no larger than a " bumming bee." But vertebrated 
 animals have fore-quarters as well as liind-quarters ; they have also a neck 
 and a head ; and, if we are to grow our bird from a true reptile, lessening 
 its size, warming its blood, and dotting it with feathers, we must graft the 
 head of the Ichthyosaurus, and the neck of the Plesiosaurus, on to the 
 hind-quarter of the Iguanodon. Now, I contend that Nature did not work 
 in this fashion. The bird had its own ancestors as much as Man had his : 
 he is not indebted to an archaic gorilla for his existence ; and the bird 
 owes nothing, in that way, to your Iguanodon, Plesiosaurus, and Ichthyo- 
 saurus. So much is clear. It is not clear as to how Nature did work : it 
 is a perfect work, but she has concealed her art. If, however, her 
 
 * See Huxley, Proceedings Geological Society, 1869, p. 31. 
 
94 Cunningham Memoirs. 
 
 beginnings were mean and small, her latter end has greatly increased. We 
 dream, scientifically, of the primordial amphibio-Dipnoan — the imagined 
 common ancestor of all the reptiles and of all the birds ; we see and handle 
 the results ; and, if the blind, unconscious morphological force could see 
 and speak, it would pronounce all these forms "very good." 
 
 These remarks are general ; we may, however, make some special 
 attempt at showing that they are " words of soberness." 
 
 The development of the bird is not a process that takes place suddenly, 
 at a leap ; but is a long, slow, metamorphic process. Each stage in the 
 development of a chick shows us the isomorph of some low adult form ; 
 each point gained gives us a quasi-historical record of -some ancient type 
 that must have belonged to a far lower platform of life than the creature 
 wdiose growth we are tracing.* Then naked, dry teleology is of very 
 little use to the morphologist ; it serves him so badly that he is in danger 
 of casting it aside altogether. Nature will not form her high and noble 
 type all at once; she will " spin her yarn" slowly and with solemnity, 
 working as with a needle in the dark. When the " tapestry " is perfected, 
 then we have the pheasant and the pea-fowl, the trogon and the hum- 
 ming-bird. 
 
 That which has dominated the whole form is the wing. Yet, 
 embryology shows us that this is merely the modified fore-paddle of a low 
 gill-breathing amphibian — a nailless fore-paw. But the nails or claws 
 do appear ; yet, in the wing, they are out of place ; and this reptilian stage 
 is only transient. If the bird is, indeed, the child of the reptile, it must 
 forget its father's house ; it must proceed beyond its progenitor. But 
 the reptile, as a rule, has a most perfect and typical " hand" or fore-foot, 
 with accurate rows of carpals and metacarpals, and with digits in fixed 
 order and number; in front two, then three, four, five, and once again, 
 four in the hinder side. 
 
 We have no sign of atavism or degradation, of abortion or of suppres- 
 sion, in the perfect fore-foot of a lizard : in a bird all these things turn up, 
 and startle the morphologist, whose hard duty it is to interpret them. 
 
 * See Philosophical Transactions, 18G9, pp. 803, 804. 
 
Mb. W. K. Parker. — Morphology of the Duck and the Auk Tribes. 95 
 
 But, if we are willing to see the bird's wing grow, not out of a perfect and 
 typical cheiropterygium, but out of an ichthyopterygium in an unsettled 
 state, ready for transformation into the higher type of limb, then the 
 difficulty is solved. It was a fish-paddle ; it was not to become a fore-foot ; 
 it did change into the framework of a bird's wing ; in that respect it is a 
 perfect thing ; as a paw, it is an abortion. 
 
 But an organism moves together in all its parts, if it moves at all ; and 
 thus we see that, in correlation to the profoundly modified fore-limb, every 
 other part of this feathered creature has suffered changes. I need not here 
 recapitulate the details of this beautiful metamorphosis.* 
 
 As bearing upon the evolution of both the bird's wing and the fore-paw 
 of the mammal, including the human hand, the most complete cheiroptery- 
 gium in existence, I would again refer to M. Dollo's memoir on Iguanodon 
 beruissastensisj-f in which the five digits of the fore-arm have their normal 
 number of reptilian segments (phalanges) in the first and second, whilst, as 
 in mammals, the fourth and fifth keep to three only. This type also shows 
 how a digit may become a spur ; for the ungual phalanx of the pollex turns 
 inwards and upwards, and forms a large defensive spur. And this is so 
 closely set upon the very solid and simple carpus as to be little different 
 from the spur of Palamedea and Chauna, among modern birds. Indeed, it 
 is difficult to say whether the small bone at the base of the ungual phalanx 
 
 * Besides the references to works and papers in the body of this memoir, I -would here 
 especially refer to some invaluable pieces of morphological work : — Morse, Dr. Edward S., "On the 
 Tarsus and Carpus of Birds."— Ann. Lye. Nat. Hist. New York. Vol. x., 1878 ; pp. 141-158, 
 Plates IV., V. Do., " On the Identity of the Ascending Process of the Astragalus in Birds with 
 the Intermedium." — Ann. Mem. Bost. Soc. Nat. Hist., 1880, pp. 1-10, Plate I. Kehrer, Gustav, 
 " Beitra'ge zur Kenntniss des Carpus und Tarsus der Amphibien, Reptilien, unci Sauger," Berichte 
 der naturforschenden Gesellsckaft zu Freiburg, i. B., Band i., pp. 1-14, Plate IV. Howes, 
 Professor G. B., " On the Carpus and Tarsus of the Anura." — Proceedings, Zoological Society, 
 1888, pp. 141-182, Plates VII.-IX. Bardeleben, Professor Karl, "On the Pre-pollex and Pre- 
 hallux, with observations on the Carpus of Theriodesmus phylarchis." — Proceedings, Zoological 
 Society, 1889, pp. 259-262, Plate XXX. Baur, Dr. &., " Ueber den TJrsprung der Extremist en 
 der Ichthyopterygia. Bericht iiber die xx. Versammlung des Oberrheinischen geologischen 
 Vereins," pp. 1-4, figs. 1-4. 
 
 t Bull. Mus. Roy. Hist. Nat. Belg., t. i., Plate IX.; and t. ii., Plates III.-V. 
 
96 Cunningham Memoirs. 
 
 in that reptile is a metacarpal or a proximal phalanx, or both in one, either 
 fused or primarily connate. But some of these Dinosaurs have the normal 
 number of phalanges in their fore-paw, as in the existing Lacertilia.* 
 
 I refer to these valuable Papers of Marsh and Dullo both as regards the 
 limbs and the limb-girdles; the foreshadowing of the remarkable rotation 
 of the pubis and ischium, so characteristic of birds, being seen also to a less 
 degree in these huge reptiles, which seem, in this respect, to have had a 
 tendency bird-ward, but missed their mark in respect of flying, a function 
 for which they were just as little adapted as the existing whales. 
 
 * Sec Amer. Jour, of Science and Art, vol. xvii., 1879, pp. 85-92, Plates III.-X. ; ibid., 
 vol. xviii., Plate III., pp. 501-505 ; and ibid., vol. xix., Plates VI. -XL, pp. 83-87, and 
 253-259. 
 
PLATE I 
 
 MORPHOLOGY OF THE DUCK AND THE AUK TRIBES. 
 
 KOYAL IEISH ACADEMY. CUNNINGHAM MEMOIRS, NO. VI. [13] 
 
98 
 
 Cunningham Memoirs. 
 
 Fig 
 
 l. 
 
 6«. 
 
 7. 
 8. 
 
 9. 
 10. 
 11. 
 
 12. 
 13. 
 
 14. 
 
 15. 
 
 EXPLANATION OE PLATE I. 
 
 Anas lobelias; 1st stage, after nine days' incubation (less mature); left 
 
 wing, inner side inverted ; drawn with pollex downwards, . 
 The same ; 1st stage ; right leg, outer side inverted, 
 The same ; 2nd stage, after nine days' incubation (more mature) ; right 
 
 wing, inner side, natural position, ...... 
 
 The same ; 2nd stage ; left leg, outer side, natural position, 
 
 The same; 1st stage; left moiety of shoulder-girdle and sternum, oute 
 
 view, ......-•••■ 
 
 The same ; 3rd stage, after twelve days' incubation ; distal part of left 
 
 wing, outer view, ......... 
 
 The same ; distal part of index of right wing, 
 
 The same ; part of the same wing as fig. 6, inner view, 
 
 The same ; 4th stage, after fourteen days' incubation ; distal part of left 
 
 wing, outer view, .......•■ 
 
 The same ; part of same wing, inner view, ..... 
 
 The same ; 3rd stage; front view of right ankle-joint, dislocated, . 
 The same ; lower part of same preparation, hinder view, 
 The same ; 4th stage ; front view of right ankle-joint, dislocated at joint, 
 The same; 5th stag'', after eighteen days' incubation; upper part of 
 
 light ankle-joint, front view, ....... 
 
 The same ; 6th stage, duckling third day after hatching ; left ankle; sec 
 
 tion through tibiale, ......... 
 
 The same ; same preparation ; section through fibulare, . 
 
 Number of 
 times magnified. 
 
 15 diameters. 
 15 diameters. 
 
 15 diameters. 
 15 diameters. 
 
 15 diameters. 
 
 15 diameters. 
 15 diameters. 
 15 diameters. 
 
 12 diameters. 
 12 diameters. 
 20 diameters. 
 20 diameters. 
 14 diameters. 
 
 14 diameters. 
 
 4 diameters. 
 4 diameters. 
 
[For List of Abbkicyjations used on this Plate, vide over.] 
 
100 
 
 Cunningham Memoi 
 
 rs. 
 
 LIST OF ABBREVIATIONS. 
 
 [Tlie Roman Numerals indicate Nerves and their Foramina.] 
 
 nc. Acetabulum. 
 
 ae.p. Acromial process of scapula. 
 
 "ij. Angulare. 
 
 al.r. Aliethnioid. 
 
 al.n. Alinasal. 
 
 in-. Articulare. 
 
 al.s. Alisphenoid. 
 
 al.sp. Aliseptal. 
 
 a. ". Antorbital. 
 
 a.s.c. Anterior semicircular canal. 
 
 at. Atlas. 
 
 a.t.r. Anterior tympanic recess. 
 
 mi. Auditory capsule. 
 
 ii.r. Axis. 
 
 b.li.br. Basi-hyobranchial. 
 
 b.lnj. Basihyal. 
 
 5.o. Basioccipital. 
 
 b.pij. Basipterygoid. 
 
 br. Ceratobranehial. 
 
 b.s. Basisphenoid. 
 
 b.t. Basitemporal. 
 
 c. Centrum and centvale. 
 c.a. Uncinate process. 
 
 cd.r. Caudal vertebra. 
 
 e.f.c. Cranio-facial cleft. 
 
 c.lnj. Cerato-hyal. 
 
 el. Clavicle. 
 
 ('0. Columella. 
 
 ep. Carpal. 
 
 cr. Coracoid and cervical rib. 
 
 cr.g. Crista galli. 
 
 c.txj. Tympanic cavity. 
 
 c.n. Ceiitralo-ulnarc. 
 
 c.v. Cervical vertebrae. 
 
 d. Dentary. 
 d.c. Distal carpal. 
 dg. Digit. 
 
 d.t. Distal tarsal. 
 
 d.r. Dorsal rib. 
 
 d.s.v. Dorso-sacral vertebrse, 
 
 d.r. Dorsal vertebra. 
 
 c.etli. Ectoethmoid. 
 
 e .ii. External nostril. 
 
 e.o. Exoccipital. 
 
 En. Eustachian opening. 
 
 /. Frontal and femur. 
 
 fb. Fibula. 
 
 fbe. 
 
 /.,„. 
 />■■ 
 
 g- 
 h. 
 
 I. (I.C. 
 
 i.n.p. 
 
 io, 
 
 i.e. 
 
 i.el. 
 
 it. 
 
 i.o.f. 
 
 i.pa. 
 
 i.tb. 
 i.tr. 
 
 J- 
 
 /. 
 
 I.e. 
 
 l.s.v. 
 
 in. 
 
 ink. 
 
 ■in. st. 
 
 mt.e. 
 
 ml.t. 
 
 nix. p. 
 
 ii. 
 
 n.px. 
 
 ob.f. 
 
 oc.c. 
 
 od.p. 
 
 op. 
 
 o.s. 
 
 p- 
 
 pa. 
 
 p.n.p. 
 
 pa.s. 
 
 pb. 
 p. el. 
 pc.p. 
 
 Fibulare. 
 
 Foramen magnum. 
 
 Furcula. 
 
 Ganglion. 
 
 Humerus. 
 
 Horizontal semicircular canal. 
 
 Intermedium. 
 
 Interarcticular cartilage. 
 
 Internal angular process. 
 
 Intel-centrum. 
 
 Internal carotid foramen. 
 
 Interclavicle. 
 
 Ilium. 
 
 Inter-orbital fenestra. 
 
 Inter-palatine. 
 
 Intermedio-radiale. 
 
 Ischium. 
 
 Inferior turbinal. 
 
 Inter-trabccula. 
 
 Jugal. 
 
 Lachrymal 
 
 Laclrrymal canal. 
 
 Lumbo-sacral vertebrae. 
 
 Mouth. 
 
 Meckel's cartilage. 
 
 Metasternum. 
 
 Metacarpal. 
 
 Metatarsal. 
 
 Maxillo-palatine, 
 
 Nasal. 
 
 Neural arch. 
 
 Notochord. 
 
 Nasal floor. 
 
 Nasal process of pre-maxil- 
 
 lary. 
 Obturator fenestra. 
 Occipital condyle. 
 Odontoidprocess. 
 Opisthotic. 
 Orbitospbeuoid. 
 Parietal. 
 Palatine. 
 
 Posterior angular process. 
 Parasphenoid. 
 Pubis. 
 
 Posterior clinoid process. 
 Postcoraeoid process of ster- 
 
 ner. 
 p.c.s. 
 
 p.e. 
 
 V0- 
 
 pi i . 
 
 p. ii. 
 
 pr.i. 
 
 pro. 
 
 pr.z. 
 
 p.s. 
 
 p. s.e. 
 
 pi.,. 
 
 pt.:. 
 
 px. 
 
 1- 
 
 aj- 
 
 r.st. 
 
 s.og. 
 sc. 
 
 S.ll. 
 
 s.i.f. 
 
 s.o. 
 
 sp. 
 
 sp.o. 
 
 sq. 
 
 s.r. 
 s.sc. 
 
 St. 
 
 st.k. 
 
 s.r. 
 
 tb. 
 t.e. 
 
 te. 
 t.eo. 
 
 ts. 
 
 u. 
 
 ue 
 it. s.r. 
 
 r. 
 v. a. 
 r.b. 
 
 Precoracoid. 
 
 Pre-costal process of ster- 
 num. 
 
 Perpendicular ethmoid. 
 
 Pterygoid. 
 
 Phalanx. 
 
 Prenasal rostrum. 
 
 Pre-ilium. 
 
 Prootic. 
 
 Pre-zygaphophysis. 
 
 Presphenoid. 
 
 Posterior semicircular canal. 
 
 Post-ilium. 
 
 Post-zygapophysis. 
 
 Premaxilla. 
 
 Quadrate. 
 
 Quadrato- jugal. 
 
 Radius. 
 
 Rostrum of basisphenoid (= 
 rostrum of parasphenoid). 
 
 Eadiale. 
 
 Rostral process of sternum. 
 
 Supra-angulare. 
 
 Scapula. 
 
 Septum nasi. 
 
 Sacro-ischiatic fenestra. 
 
 Supra-occipital. 
 
 Splenial. 
 
 Spbenotic. 
 
 Squamosal. 
 
 Sacral rib. 
 
 Supra-scapula. 
 
 Sternum. 
 
 Sternal keel. 
 
 Sacral vertebra. 
 
 Tibial. 
 
 Tendon-canal. 
 
 Tibiale. 
 
 Tympanic wing of occipital. 
 
 Tarsal. 
 
 Ulna. 
 
 Ulnare. 
 
 Uro-sacral vertebra?. 
 
 Vomer. 
 
 Vertebral artery. 
 
 Vestibule. 
 
RL. IRISH ACAD 
 
 CUNNINGHAM MEMOIR:VI. Plate i 
 
 WKParker del adnal iMP Parker, kth 
 
 .: an, imp 
 
 ANATHXE 
 
PLATE II. 
 
 MORPHOLOGY OF THE DUCK AND THE AUK TRIBES. 
 
 ROYAL HUSH ACADEMY. CUNNINGHAM MEMOIRS, NO. VI. [14] 
 
102 
 
 C 'unningharn Memoirs. 
 
 Fig. 
 1. 
 
 3. 
 
 EXPLANATION OF PLATE II. 
 
 Anas hosclias ; 1st stage; left side of pelvis and hinder part of spine, outer 
 view, 
 
 The same ; 2nd stage ; a similar view of the same parts, .... 
 
 The same ; 3rd stage ; twelve days' incubation ; a similar view of the same 
 parts, with the pelvis somewhat dislocated from the spinal column, 
 
 The same ; 5th stage ; eighteen days' incubation ; distal part of left wing, 
 outer view, ........... 
 
 part uf same object, inner view, ...... 
 
 part of the same as fig. 4, ...... . 
 
 6th stage ; ripe embryo distal part of wing, outer view, 
 
 part of same preparation, outer view, ..... 
 
 same object ; inner view, ....... 
 
 7th stage ; proximal part of manus, outer view, 
 
 same object ; inner view, ....... 
 
 7th stage ; another specimen ; coccygeal tract of spine ; side 
 
 5. 
 
 The same 
 
 6. 
 
 The same 
 
 7. 
 
 The same 
 
 8. 
 
 The same 
 
 9. 
 
 The same 
 
 10. 
 
 The same 
 
 11. 
 
 The same 
 
 12. 
 
 The same 
 
 
 view, 
 
 Number of 
 times magnified. 
 
 16 diameters. 
 12 diameters. 
 
 9-J diameters. 
 
 9J diameters. 
 19 diameters. 
 29 diameters. 
 8 diameters. 
 16 diameters. 
 16 diameters. 
 10 diameters. 
 10 diameters. 
 
 5 diameters. 
 
 13. CJtauna ehararia ; adult; distal end of ulnar, -with carpals, . . . J Natural size. 
 
 14. Cygnus atratus ; part of palate, ........ J Natural size. 
 
 15. Anser palustris six 'weeks old ; vomer and antero-superior additional 
 
 ossicle ; lateral and upper views, 
 
 2i diameters. 
 
[For List of Abbreviations used on this Plate, vide over.] 
 
104 
 
 Cunningham Memoirs. 
 
 LIST OF ABBEEVIATIONS. 
 
 [The Roman Numerals indicate Nerves and their Foramina. ,] 
 
 tic. 
 
 Acetabulum. 
 
 fie. 
 
 Fibulare. 
 
 per. 
 
 Precoracoid. 
 
 ac.p 
 
 Acromial process of scapula. 
 
 f.m. 
 
 Foramen magnum. 
 
 p.c.s. 
 
 Pre-costal process of ster- 
 
 « ti- 
 
 Angulare. 
 
 /''■ 
 
 Furcula. 
 
 
 num. 
 
 ttle. 
 
 Aliethmoid. 
 
 9- 
 
 Ganglion. 
 
 p.e. 
 
 Perpendicular ethmoid. 
 
 al. it 
 
 Alinasal. 
 
 h. 
 
 Humerus. 
 
 P'J- 
 
 Pterygoid. 
 
 Ul\ 
 
 Articulare. 
 
 h.s.c. 
 
 Horizontal semicircular canal. 
 
 ph. 
 
 Phalanx. 
 
 all. 
 
 Alisphenoid. 
 
 i. 
 
 Intermedium. 
 
 p. n. 
 
 Prenasal rostrum. 
 
 al.sp. 
 
 Aliseptal. 
 
 i.ii.c. 
 
 Interareticular cartilage. 
 
 pr.i. 
 
 Pre-ilium. 
 
 (7.0. 
 
 Antorbital. 
 
 i.a.p. 
 
 Internal angular process. 
 
 pro. 
 
 Prootic. 
 
 a.s.c. 
 
 Anterior semicircular canal. 
 
 ic. 
 
 Intercentrum. 
 
 pr.z. 
 
 Tre-zygapliophysis . 
 
 ut. 
 
 Atlas. 
 
 i.e. 
 
 Internal carotid foramen. 
 
 p.s. 
 
 Presphenoid. 
 
 a.t.r. 
 
 Anterior tympanic recess. 
 
 i.cl. 
 
 Interclavicle. 
 
 p. .i.e. 
 
 Posterior semicircular canal 
 
 tin. 
 
 Auditory capsule. 
 
 il. 
 
 Ilium. 
 
 pt.i. 
 
 Post-ilium. 
 
 ax. 
 
 Axis. 
 
 i.o.f. 
 
 Inter-orbital fenestra. 
 
 pt.z. 
 
 Post-zygapophysis. 
 
 b. It. hi- 
 
 Basi-liyoliranchial. 
 
 i.pa. 
 
 Inter-palatine. 
 
 px. 
 
 Premaxilla. 
 
 ll, h ij . 
 
 Basihyal. 
 
 l.r. 
 
 Intermedio-radiale. 
 
 ?• 
 
 Quadrate. 
 
 bio. 
 
 Basioccipital. 
 
 ise. 
 
 Ischium. 
 
 <1-J- 
 
 Quadrato-jugal. 
 
 b.jy. 
 
 Basipterygoid. 
 
 i.tb. 
 
 Inferior turbinal. 
 
 r. 
 
 Radius. 
 
 l»: 
 
 Ceratobranchial. 
 
 i.tr. 
 
 Inter-trabecula. 
 
 r.b.i. 
 
 Rostrum of basisphenoid (= 
 
 b.s. 
 
 Basispbenoid. 
 
 J- 
 
 Jugal. 
 
 
 rostrum of parasphenoid). 
 
 b.t. 
 
 Basitemporal. 
 
 1. 
 
 Lachrymal. 
 
 re. 
 
 Radialc. 
 
 c. 
 
 Centrum and centrale. 
 
 I.e. 
 
 Lachrymal canal. 
 
 r.st. 
 
 Rostral process of sternum. 
 
 C.ll. 
 
 Uncinate process. 
 
 Ls.v. 
 
 Lumbo-saoral vertebra;. 
 
 S.llff. 
 
 Supra-angulare. 
 
 Cll.f. 
 
 Caudal vertebra. 
 
 in. 
 
 Mouth. 
 
 sc. 
 
 Scapula. 
 
 c.f.c. 
 
 Cranio-facial cleft. 
 
 ink. 
 
 Meckel's cartilage. 
 
 S.ll. 
 
 Septum nasi. 
 
 c.hij. 
 
 Cerato-byal. 
 
 III. St. 
 
 Metastemum. 
 
 s.i.f. 
 
 Sacro-ischiatic fenestra. 
 
 el. 
 
 Clavicle. 
 
 Illt.C. 
 
 Metacarpal. 
 
 s.o. 
 
 Supra-occipital. 
 
 CO. 
 
 Columella. 
 
 mt.t. 
 
 Metatarsal. 
 
 sp. 
 
 Splenial. 
 
 cp. 
 
 Carpal. 
 
 i'i.c./i. 
 
 Maxillo-palatine. 
 
 sp.o. 
 
 Sphenotic. 
 
 cr. 
 
 Coracoid and cervical rib. 
 
 n. 
 
 Nasal. 
 
 sip 
 
 Squamosal. 
 
 cr.g. 
 
 Crista galli. 
 
 ■n. a. 
 
 Neural arch. 
 
 l.r. 
 
 Sacral rib. 
 
 e.ty. 
 
 Tympanic cavity. 
 
 nc. 
 
 Notochord. 
 
 s.ie. 
 
 Supra-scapula. 
 
 C.ll. 
 
 Centralo-ulnare. 
 
 «,/'. 
 
 Nasal floor. 
 
 St. 
 
 Sternum. 
 
 e.v. 
 
 Cervical vertebras. 
 
 n.px. 
 
 Nasal process of pre-ruaxil- 
 
 st./t. 
 
 Sternal keel. 
 
 ll. 
 
 Dentary. 
 
 
 lary. 
 
 s.r. 
 
 Sacral vertebra. 
 
 d.c. 
 
 Distal carpal. 
 
 ob.f. 
 
 Obturator fenestra. 
 
 tb. 
 
 Tibial. 
 
 thj. 
 
 Digit. 
 
 oc.c. 
 
 Occipital condyle. 
 
 t.c. 
 
 Tendon-canal. 
 
 d.t. 
 
 Distal tarsal. 
 
 Oil. p. 
 
 Odontoidprocess. 
 
 te. 
 
 Tibiale. 
 
 tie. 
 
 Dorsal rib. 
 
 op. 
 
 Opisthotie. 
 
 t.eo. 
 
 Tympanic wing of occipital 
 
 d.s.v. 
 
 Dorso-sacral vertebras, 
 
 o.s. 
 
 Orbitosphenoid. 
 
 ts. 
 
 Tarsal. 
 
 d.v. 
 
 Dorsal vertebra. 
 
 p- 
 
 Parietal. 
 
 u. 
 
 Ulna. 
 
 e.eth. 
 
 Ectoetbmoid. 
 
 pa. 
 
 Palatine. 
 
 lie. 
 
 Ulnare. 
 
 C.ll. 
 
 External nostril. 
 
 p. a. p. 
 
 Posterior angular process. 
 
 II.S.V. 
 
 Uro-sacral vertebrae. 
 
 e.o. 
 
 Exoccipital. 
 
 pu.s. 
 
 Parasphenoid. 
 
 v. 
 
 Vomer. 
 
 En. 
 
 Eustachian opening. 
 
 pb. 
 
 Pubis. 
 
 v. a. 
 
 Vertebral artery. 
 
 /■ 
 
 Frontal and femur. 
 
 p.cl. 
 
 Posterior clinoid process. 
 
 v.b. 
 
 Vestibule. 
 
 fb. 
 
 Fibula. 
 
 pep. 
 
 Postcoracoid process of ster- 
 num. 
 
 
 
RL. IRISH ACAD 
 
 CUNNINGHAM MEMOIR: VI . Plate 2. 
 
 . ker del ad.i^v Id I ■ . 
 
 ■ 
 
 ANAT ID At . 
 
PLATE III 
 
 MORPHOLOGY OF THE DUCK AND THE AUK TRIBES. 
 
 KOTAL IRISH ACADEMY. CUNNINGHAM" MEMOIRS, NO. VI. [^ 5 ] 
 
108 
 
 Cunningham Memoirs. 
 
 LIST OF ABBREVIATIONS. 
 
 
 [ The Roman 
 
 Numerals indicate Jyerces ana t 
 
 heir J! 
 
 oramma.J 
 
 ae. 
 
 Acetabulum. 
 
 /be. 
 
 Fibulare. 
 
 per. 
 
 Precoracoid. 
 
 ac.p. 
 
 Acromial process of scapula. 
 
 f.m. 
 
 Foramen magnum. 
 
 p.c.s. 
 
 Pre-costal process of ster- 
 
 ag. 
 
 Angulare. 
 
 />■ 
 
 Furcula. 
 
 
 num. 
 
 al.e. 
 
 Aliethmoid. 
 
 ff- 
 
 Ganglion. 
 
 p.e. 
 
 Perpendicular ethmoid. 
 
 al.n. 
 
 Alinasal. 
 
 h. 
 
 Humerus. 
 
 pg- 
 
 Pterygoid. 
 
 ar. 
 
 Articulare. 
 
 h.s.c. 
 
 Horizontal semicircular canal. 
 
 ph. 
 
 Phalanx. 
 
 al.s. 
 
 AlisplrenoiJ. 
 
 i. 
 
 Intermedium. 
 
 p. it. 
 
 Prenasal rostrum. 
 
 al.sp. 
 
 Aliseptal. 
 
 i.a.c. 
 
 Interarcticular cartilage. 
 
 pr.i. 
 
 Pie-ilium. 
 
 a.o. 
 
 Antorbital. 
 
 i.a.p. 
 
 Internal angular process. 
 
 pro. 
 
 Prootic. 
 
 a.s.e. 
 
 Anterior semicircular canal. 
 
 ic. 
 
 Intercentrum. 
 
 pr.z. 
 
 Tre-zygaphophysis. 
 
 at. 
 
 Atlas. 
 
 i.e. 
 
 Internal carotid foramen. 
 
 p.s. 
 
 Presphenoid. 
 
 a.t.r. 
 
 Anterior tympanic recess. 
 
 i.cl. 
 
 Interclavicle. 
 
 p.s.c. 
 
 Posterior semicircular canal 
 
 ait. 
 
 Auditory capsule. 
 
 il. 
 
 Ilium. 
 
 pt.i. 
 
 Post-ilium. 
 
 ax. 
 
 Axis. 
 
 i.o.f. 
 
 Inter-orbital fenestra. 
 
 pt.z. 
 
 Post-zygapophysis. 
 
 b.h.hr. 
 
 Basi-hyobranchial. 
 
 i.pa. 
 
 Inter-palatine. 
 
 px. 
 
 Premaxilla. 
 
 h.luj. 
 
 Basiliyal. 
 
 i.r. 
 
 Intermedio-radiale. 
 
 <?• 
 
 Quadrate. 
 
 i.o. 
 
 Basioccipital. 
 
 isc. 
 
 Ischium. 
 
 q-j- 
 
 Quadrato-jugal. 
 
 b.pg. 
 
 Basipterygoid. 
 
 i.tb. 
 
 Inferior turbinal. 
 
 r. 
 
 Radius. 
 
 br. 
 
 Ceratobranchial. 
 
 i.tr. 
 
 Inter-trabecula. 
 
 r.b.s. 
 
 Rostrum of basisphenoid (= 
 
 b.s. 
 
 Basisphenoid. 
 
 J- 
 
 Jugal. 
 
 
 rostrum of parasphenoid). 
 
 b.t. 
 
 Basiteniporal. 
 
 I. 
 
 Lachrymal. 
 
 re. 
 
 Radiale. 
 
 c. 
 
 Centrum and centrale. 
 
 I.e. 
 
 Lachrymal canal. 
 
 r.st. 
 
 Rostral process of sternum. 
 
 c.a. 
 
 Uncinate process. 
 
 l.s.v. 
 
 Lumbo-sacral vertebra 1 . 
 
 s.ag. 
 
 Supra-augulare. 
 
 ccl.r. 
 
 Caudal vertebra. 
 
 in. 
 
 Mouth. 
 
 se. 
 
 Scapula. 
 
 c.f.e. 
 
 C'rauio-facial cleft. 
 
 ml;. 
 
 Meckel's cartilage. 
 
 S.ll. 
 
 Septum nasi. 
 
 o.hy. 
 
 el. 
 
 Cerato-kyal. 
 
 m.st. 
 
 Metasternum. 
 
 s.i.f. 
 
 Sacro-ischiatic fenestra. 
 
 Clavicle. 
 
 mt.e. 
 
 Metacarpal. 
 
 s.o. 
 
 Supra-occipital. 
 
 CO. 
 
 Columella. 
 
 mt.t. 
 
 Metatarsal. 
 
 sp. 
 
 Splenial. 
 
 cp. 
 
 Carpal. 
 
 ■m.v.p. 
 
 Maxillo-palatine. 
 
 sp.o. 
 
 Splienotic. 
 
 cr. 
 
 Coracoid and cervical rib. 
 
 >t. 
 
 Nasal. 
 
 so. 
 
 Squamosal. 
 
 cr.g. 
 
 Crista galli. 
 
 it. a. 
 
 Neural arch. 
 
 i.r. 
 
 Sacral rib. 
 
 <•■'.'/• 
 
 Tympanic cavity. 
 
 nc. 
 
 Notochord. 
 
 s.se. 
 
 Supra-scapula. 
 
 C.ll. 
 
 Centralo-uluave. 
 
 n.f. 
 
 Nasal floor. 
 
 St. 
 
 Sternum. 
 
 C.V. 
 
 Cervical vertebra;. 
 
 n.px. 
 
 Nasal process of pre-maxil- 
 
 st./;. 
 
 Sternal keel. 
 
 d. 
 
 Dentary. 
 
 
 lary. 
 
 s.v. 
 
 Sacral vertebra. 
 
 i.e. 
 
 Distal carpal. 
 
 ob.f. 
 
 Obturator fenestra. 
 
 tb. 
 
 Tibial. 
 
 dg. 
 
 Digit. 
 
 oc.c. 
 
 Occipital condyle. 
 
 t.c. 
 
 Tendon-canal. 
 
 d.t. 
 
 Distal tarsal. 
 
 od.p. 
 
 Odontoidprocess. 
 
 te. 
 
 Tibiale. 
 
 d.r. 
 
 Dorsal rib. 
 
 op. 
 
 Opisthotic. 
 
 t.eo. 
 
 Tympanic wing of occipital 
 
 d.s.v. 
 
 Dorso-sacral vertebras, 
 
 o.s. 
 
 Orbitosphenoid. 
 
 ts 
 
 Tarsal. 
 
 d.v. 
 
 Dorsal vertebra. 
 
 V- 
 
 Parietal. 
 
 u. 
 
 Ulna. 
 
 e.eth. 
 
 Ectoetbmoid. 
 
 pa. 
 
 Palatine. 
 
 lie 
 
 Uluare. 
 
 e.n 
 
 External nostril. 
 
 p.a.p. 
 
 Posterior angular process. 
 
 11. s.v. 
 
 Uro- sacral vertebra;. 
 
 e.o. 
 
 Exoecipital. 
 
 pa.s. 
 
 Parasphenoid. 
 
 v. 
 
 Yorner. 
 
 En. 
 
 Eustachian opening. 
 
 pb. 
 
 Pubis. 
 
 v. a. 
 
 Vertebral artery. 
 
 f. 
 
 Frontal and femur. 
 
 p.cl. 
 
 Posterior clinoid process. 
 
 v.b. 
 
 Vestibule. 
 
 fb. 
 
 Fibula. 
 
 pep. 
 
 Postcoracoid process of ster- 
 num. 
 
 
 
RL. IRISH ACAD. 
 
 CUNNINGHAM MEMOIR: VI. Plate 3. 
 
 m 
 
 WKParW del .ad. nat.MPPii:'li:»:- '.:!_'.. 
 
 WestJ3ewzna.il imp 
 
 ' 
 
PLATE IV 
 
 MORPHOLOGY OF THE DUCK AND THE AUK TRIBES. 
 
 BOYAL IEISH ACADEMY. CUNNINGHAM MEMOIRS, NO. VI. [16] 
 
110 Cunningham Memoirs. 
 
 EXPLANATION OF PLATE IV. 
 
 Number of 
 Fig. times magnified. 
 
 1. Cygnus nigricollis ; nearly ripe skeleton ; side view, . . . 3 diameters. 
 
[For List of Abbbeviations used on this Plate, vide over. J 
 
112 
 
 Cunningham Memoirs. 
 
 LIST OF ABBREVIATIONS. 
 
 [_The Roman Numerals indicate Nerves and their Foramina.'] 
 
 ae. 
 
 Acetabulum. 
 
 fte. 
 
 Fibulare. 
 
 per. 
 
 Precoracoid. 
 
 ac.p. 
 
 Acromial process of scapula. 
 
 f.m. 
 
 Foramen magnum. 
 
 p.c.s. 
 
 Pre-costal process of ster- 
 
 ag. 
 
 Annulare. 
 
 /''• 
 
 Furcula. 
 
 
 num. 
 
 al.e. 
 
 Aliethmoid. 
 
 9- 
 
 Ganglion. 
 
 p.e. 
 
 Perpendicular ethmoid. 
 
 a2.ii. 
 
 Alinasal. 
 
 h. 
 
 Humerus. 
 
 pg- 
 
 Pterygoid. 
 
 ar. 
 
 Arliculare. 
 
 h.s.c. 
 
 Horizontal semicircular canal. 
 
 ph. 
 
 Phalanx. 
 
 al.s. 
 
 Alisphenoid. 
 
 i. 
 
 Intermedium. 
 
 p. u. 
 
 Prenasal rostrum. 
 
 al.sp. 
 
 Aliseptal. 
 
 i.n.e. 
 
 Interarcticular cartilage. 
 
 pr.i. 
 
 pre-ilium. 
 
 a.o. 
 
 Antorbital. 
 
 i.a.p. 
 
 Internal angular process. 
 
 pro. 
 
 Prootie. 
 
 a.s.c. 
 
 Anterior semicircular canal. 
 
 ic. 
 
 Intereentrum. 
 
 pr.:. 
 
 Pre-zygaphophysis. 
 
 at. 
 
 Atlas. 
 
 i.e. 
 
 Internal carotid foramen. 
 
 p.s. 
 
 Presphenoid. 
 
 a.t.r. 
 
 Anterior tympanic recess. 
 
 i.cl. 
 
 Interclaviele. 
 
 p.S.C. 
 
 Posterior semicircular canal 
 
 an. 
 
 Auditory capsule. 
 
 it. 
 
 Ilium. 
 
 pt.i. 
 
 Post-ilium. 
 
 ax. 
 
 Axis. 
 
 i.o.f. 
 
 Inter-orbital fenestra . 
 
 pt.z. 
 
 Post-z ygapophysis . 
 
 li.li.br. 
 
 Basi-hyobranchial. 
 
 i.pa. 
 
 Inter-palatine. 
 
 px. 
 
 Premaxilla. 
 
 h.lnj. 
 
 Basihyal. 
 
 i.r. 
 
 Inl ermedio-radiale. 
 
 <]■ 
 
 Quadrate. 
 
 b.o. 
 
 Basioccipital. 
 
 isc. 
 
 Ischium. 
 
 IJ-j- 
 
 Quadrato-jugal. 
 
 b.pg. 
 
 Basipterygoid. 
 
 i.tb. 
 
 Inferior turbinal. 
 
 r. 
 
 Radius. 
 
 In: 
 
 Ceratobrancliial. 
 
 i.tr. 
 
 Inter-trabecula. 
 
 r.b.s. 
 
 Rostrum of basisplienoid (= 
 
 t.8. 
 
 Basisplienoid. 
 
 ./'■ 
 
 Jugal. 
 
 
 rostrum of parasphenoid) . 
 
 b.t. 
 
 Basitemporal. 
 
 1. 
 
 Lachrymal, 
 
 re 
 
 Radiale. 
 
 c. 
 
 Centrum and centrale. 
 
 I.e. 
 
 Lachrymal canal. 
 
 r.st. 
 
 Rostral process of sternum. 
 
 C.ll. 
 
 Uncinate process. 
 
 I.s.v. 
 
 Lumbo-sacral vertebra" 1 . 
 
 s.ng. 
 
 Supra-angulare. 
 
 cd.v. 
 
 Caudal vertebra. 
 
 in. 
 
 Mouth. 
 
 SC. 
 
 Scapula. 
 
 city, 
 el. 
 
 Cranio-facial cleft. 
 
 ml;. 
 
 "Meckel's cartilage. 
 
 s.n. 
 
 Septum nasi. 
 
 Cerato-hyal. 
 Clavicle. 
 
 III. si. 
 
 Metasternum. 
 
 s.i.f. 
 
 Saero-ischiatic fenestra. 
 
 lllt.C. 
 
 Metacarpal. 
 
 s.o. 
 
 Supra-occipital. 
 
 CO. 
 
 Columella. 
 
 nil.t. 
 
 Metatarsal. 
 
 sp. 
 
 Splenial. 
 
 ep. 
 
 Carpal. 
 
 mx.p. 
 
 Maxillo-palatine. 
 
 Sp.O. 
 
 Spbenotic. 
 
 cr. 
 
 Coracoid and cervical rib. 
 
 it. 
 
 Nasal. 
 
 sq. 
 
 Squamosal. 
 
 er.g. 
 
 Crista galli. 
 
 n.a. 
 
 Neural arch. 
 
 s.r. 
 
 Sacral rib. 
 
 '•■ ttj. 
 
 Tympanic cavity. 
 
 ne. 
 
 Notochord. 
 
 s.se. 
 
 Supra-scapula. 
 
 C.ll. 
 
 Ccntralo-ulmire. 
 
 n.f. 
 
 Nasal floor. 
 
 St. 
 
 Sternum. 
 
 r.r. 
 
 Cervical vertebra;. 
 
 n.px. 
 
 Nasal process of pre-maxi 1 - 
 
 St./,. 
 
 Sternal keel. 
 
 d. 
 
 Dentary. 
 
 
 lary. 
 
 s.r. 
 
 Sacral vertebra. 
 
 d.c. 
 
 Distal carpal. 
 
 ob.f. 
 
 Obturator fenestra. 
 
 tb. 
 
 Tibial. 
 
 ,hj. 
 d.t. 
 
 Digit. 
 
 oc.c. 
 
 Occipital condyle. 
 
 t.C. 
 
 Tendon-canal. 
 
 Distal tarsal. 
 
 od.p. 
 
 Odontoidprocess. 
 
 te. 
 
 Tibiale. 
 
 d.r. 
 
 Dorsal rib. 
 
 op. 
 
 Opisthotic. 
 
 t.co. 
 
 Tympanic wing of occipital 
 
 d.s.v. 
 
 Dorso-sacral vertebra:, 
 
 o.s. 
 
 Orbitospbenoid. 
 
 ts. 
 
 Tarsal. 
 
 d.v. 
 
 Dorsal vertebra. 
 
 p- 
 
 Parietal. 
 
 71. 
 
 Ulna. 
 
 , jili. 
 
 Ectoethnioid. 
 
 pa. 
 
 Palatine. 
 
 ne 
 
 Ulnare. 
 
 c.ll. 
 
 External nostril. 
 
 p.a.p. 
 
 Posterior angular process. 
 
 u.s.r. 
 
 Uro- sacral vertebra:. 
 
 CO. 
 
 Exoccipital. 
 
 pa.s. 
 
 Parasphenoid. 
 
 v. 
 
 Vomer. 
 
 En. 
 
 Eustachian opening. 
 
 P b. 
 
 Pubis. 
 
 v.a. 
 
 Vertebral artery. 
 
 f. 
 
 Frontal and femur. 
 
 p.cl. 
 
 Posterior clinoid process. 
 
 v.b. 
 
 Vestibule. 
 
 ft. 
 
 Fibula. 
 
 pep. 
 
 Postcoracoid process of ster- 
 num. 
 
 
 
RL. IRISH ACAD. 
 
 CUNNINGHAM MEMOIR-. VI .Plate 4. 
 
 W !v F ■ -,-,- d.l ainat K P Parker kth 
 
PLATE V, 
 
 MORPHOLOGY OF THE DUCK AND THE AUK TRIBES. 
 
 ri7l 
 
 ROYAL IRISH ACADEMY. CUNNINGHAM MKMOISS, NO. VI. i_*'J 
 
114 
 
 Cunningham Memoirs. 
 
 Fig 
 
 3. 
 
 4. 
 
 5. 
 
 6. 
 
 7. 
 
 8. 
 
 9. 
 10. 
 11. 
 
 12. 
 13. 
 
 14. 
 
 EXPLANATION OF PLATE V. 
 
 Cygnm olor ; («) cygnet 141 inches long ; skull in vertical section 
 
 The same ; (a) atlas and axis ; side view, . . . . 
 
 The same ; («■) section of the first three cervical vertebrae, 
 
 The same ; (5) cygnet 15 inches long; part of atlas ; side view, 
 
 The same ; (a) centrum of 2.5th part of 24th cervical vertebrae ; horizontal 
 section near lower surface, .... 
 
 The same ; (b) terminal part of spinal column ; side view 
 
 Tin same ; same object; lower view, 
 
 The same ; (a) distal part of wing ; inner view, 
 
 The same ; («) ankle-joint ; inner view, 
 
 The same ; same object ; outer view, 
 
 The same ; same object; front view, 
 
 The same ; (b) pelvis ; lower view, 
 
 Chlo'ephaga poliocepJiala, ripe embryo ; distal p 
 The same ; same object ; inner view, 
 The same ; part of fig. 13, 
 
 lit of wing ; outer view, 
 
 Number of 
 times magnified. 
 
 2 diameters. 
 
 3 diameters. 
 3 diameters. 
 6 diameters. 
 
 3 diameters. 
 3 diameters. 
 3 diameters. 
 3 diameters. 
 2 diameters. 
 2 diameters. 
 
 2 diameters. 
 1 1 diameters. 
 
 3 diameters. 
 3 diameters. 
 G diameters. 
 
[For List of Abbreviations used on this Plato, vide over.l 
 
116 
 
 Cunningham Memoirs. 
 
 LIST OF ABBEEVIATIONS. 
 
 [The Roman Numerals indicate Nerves 
 
 and their Fo, 
 
 ac. Acetabulum. 
 
 ae. p. Acromial process of scapula. 
 
 ag. Angulave. 
 
 al.c. Alietlimoid. 
 
 al.ii. Alinasal. 
 
 nr. Artieulare. 
 
 al.s. Alisphenoid. 
 
 al.sp. Aliseptal. 
 
 a.o. Antorbital. 
 
 a.s.e. Anterior semicircular canal. 
 
 at. Atlas. 
 
 a.t.r. Anterior tympanic recess. 
 
 an. Auditor}' capsule. 
 
 ax. Axis. 
 
 b. lt.br. Basi-hyobranchial. 
 
 b.luj. Basihyal. 
 
 b.o. Basioccipital. 
 
 b.pg. Basipterygoid. 
 
 br. Ceratobranchial. 
 
 b.s. Basisphcnoid. 
 
 h.t. Basitemporal. 
 
 c. Centrum and centrale. 
 c.a. Uncinate process. 
 
 cd.v. Caudal vertebra. 
 
 c.f.c. Crauio-facial cleft. 
 
 e.Iiij. Cerato-hyal. 
 
 cl. Clavicle. 
 
 co. Columella. 
 
 ep. Carpal. 
 
 cr. Coracoid and cervical rib. 
 
 cr.ff. Crista galli. 
 
 c.tg. Tympanic cavity. 
 
 at. Centralo-ulnare. 
 
 (-.!'. Cervical vertebrae. 
 
 d. Dent uy. 
 d.c. Distal carpal. 
 dg. Digit. 
 
 d.t. Distal tarsal. 
 
 d.r. Dorsal rib. 
 
 d.s.v. Dorso-sacral vertebra;, 
 
 d.r. Dorsal vertebra. 
 
 e.eth. Ectoetbmoid. 
 
 e.n. External nostril. 
 
 e.o. Exoccipital. 
 
 En. Eustachian opening. 
 
 /. Frontal and femur. 
 
 fb. Fibula. 
 
 fbc. Fibulare. 
 
 f.m. Foramen magnum. 
 
 fr. Furcula. 
 
 g. Ganglion. 
 
 h. Humerus. 
 
 Ji.s.c. Horizontal semicircular canal. 
 
 i. Intermedium. 
 
 i.a.e. Interarctieular cartilage. 
 
 i.a.p. Internal angular process. 
 
 ic. Intercentrum. 
 
 i.e. Internal carotid foramen. 
 
 i.cl. Interelavicle. 
 
 it. Ilium. 
 
 i.o.f. Inter-orbital fenestra. 
 
 i.pa. Inter-palatine. 
 
 i.r. Intermedio-radiale. 
 
 isc. Ischium. 
 
 i.lb. Inferior turbinal. 
 
 i.tr. Inter-tralieeula. 
 
 j. Jugal. 
 
 I. Lachrymal. 
 
 I.e. Lachrymal canal. 
 
 l.s.v. Lumho-sacral vertebrae. 
 
 in. Mouth. 
 
 ink. Meckel's cartilage. 
 
 7ii. sL Metasternum. 
 
 int.e. Metacarpal. 
 
 mt.t. Metatarsal. 
 
 mx.p. Maxillo-palatine. 
 
 n. Nasal. 
 
 ii. a. Neural arch. 
 
 iic. Notocliord. 
 
 n.f. Nasal floor. 
 
 n.p.r. Nasal process of pre-maxil- 
 
 lary. 
 
 ob.f. Obturator fenestra. 
 
 oc.c. Occipital condyle. 
 
 od.p. Odontoidprocess. 
 
 op. Opisthotic. 
 
 o.s. Orbitosphenoid. 
 
 p. Parietal. 
 
 pa. Palatine. 
 
 p. a. p. Posterior angular process. 
 
 pa.s. Parasphenoid. 
 
 pb. Pubis. 
 
 p. el. Posterior clinoid process. 
 
 pep. Posteoracoid process of ster- 
 num. 
 
 per. 
 p.e.s. 
 
 p.e. 
 
 P'J- 
 
 ph. 
 
 p. It. 
 
 pr.i. 
 
 pro 
 
 pr.z. 
 
 p.s. 
 
 2).s.e. 
 
 pl.t. 
 
 pt.z. 
 
 p.r. 
 
 ']■ 
 
 'j:i- 
 
 r. 
 r.b.s. 
 
 r.st. 
 
 s.ag. 
 sc. 
 
 S.ll. 
 
 s.i.f. 
 
 s.o. 
 sp. 
 sp.o. 
 sq. 
 s.r. 
 s.se. 
 
 St. 
 .st. I.'. 
 
 s.r. 
 
 lb. 
 t.e. 
 
 te. 
 t.co. 
 
 Is. 
 
 V. 
 
 ■ne. 
 
 it. s.r. 
 
 v. 
 
 v.a. 
 
 v.b. 
 
 Preeoracoid. 
 
 Pre-costal process of ster- 
 num. 
 
 Perpendicular ethmoid . 
 
 Pterygoid. 
 
 Phalanx. 
 
 Prenasal rostrum. 
 
 Pre- ilium. 
 
 Prootic. 
 
 Pre-zygaphophysis. 
 
 Presphenoid. 
 
 Posterior semicircular canal. 
 
 Post-ilium. 
 
 Post -z ygapophysis . 
 
 Premaxilla. 
 
 Quadrate. 
 
 Quadrato-jugal. 
 
 Radius. 
 
 Rostrum of basisphenoid (= 
 rostrum of parasphenoid) . 
 
 Radiale. 
 
 Rostral process of sternum. 
 
 S upra-angulare. 
 
 Scapula . 
 
 Septum nasi. 
 
 Sacro-ischiatic fenestra. 
 
 Supra-occipital. 
 
 Splenial. 
 
 Sphenotic. 
 
 Squamosal. 
 
 Sacral rib. 
 
 Supra-scapula. 
 
 Sternum. 
 
 Sternal keel. 
 
 Sacral vertebra. 
 
 Tibial. 
 
 Tendon-canal. 
 
 Tibiale. 
 
 Tympanic wing of occipital. 
 
 Tarsal. 
 
 Ulna. 
 
 Ulnare. 
 
 Uro- sacral vertebra?. 
 
 Vomer. 
 
 Vertebral artery. 
 
 Vestibule. 
 
RL. IRISH ACAD. 
 
 CUNNINGHAM MEMOIR: VI. Plate 5. 
 
 <§a "" @S*W 
 
 
 Lit- 
 
 •->•" i^gr 
 
 > 
 
 1 ft 
 
 -/? x 
 
 "-'-'''".'-' 
 
 W KParker Aelainat .MPEirfcr lltb 
 
 West.Nrjwinan i-ititj 
 
 ANATID/E 
 
PLAT E VI. 
 
 MORPHOLOGY OF THE DUCK AND THE AUK TRIBES. 
 
 ROYAL ntTSH ACADEMY. CUNNINGHAM MEMOIRS, NO. VI. 
 
 ri8i 
 
118 
 
 Cunningham Memoirs. 
 
 EXPLANATION OF PLATE VI. 
 
 Fig. 
 
 1 Uria troile ; 1 st stage ; embryo, one-third ripe ; skull ; lower view, 
 
 2. The same ; mandible of same stage ; inner view, .... 
 
 3. The same ; hyoid arch ; upper view, ...... 
 
 4. The same ; 2nd stage ; embryo two-thirds ripe ; skull ; lower view, 
 
 5. The same ; same skull ; upper view, ...... 
 
 6. The same ; mandible of same skull ; inner view, .... 
 
 7. The same ; hyoid arch of same skull ; upper view, . 
 
 8. The same ; 3rd stage ; embryo, nearly ripe ; section of skull, and innei 
 
 view of mandible, ••....... 
 
 Number of 
 times magnified. 
 
 6 -} diameters. 
 6*- diameters. 
 6-J- diameters. 
 
 4 diameters. 
 
 4 diameters. 
 
 4 diameters. 
 
 4 diameters. 
 
 4 diameters. 
 
[For List of Abbreviations used on this Plate, vide over.] 
 
120 
 
 Cunningham Memoirs. 
 
 LIST OF ABBEEVIATIONS. 
 
 [The Roman Numerals indicate' Nerves and their Foramina.'] 
 
 ae. 
 
 Acetabulum. 
 
 fie. 
 
 Fibulare. 
 
 per. 
 
 Precoracoid. 
 
 ac.p. 
 
 Acromial process of scapula. 
 
 f.m. 
 
 Foramen magnum. 
 
 p.c.s. 
 
 Pre-costal process of ster- 
 
 ag. 
 
 Angulare. 
 
 fr- 
 
 Fureula. 
 
 
 num. 
 
 al.e. 
 
 Aliethmoid. 
 
 a- 
 
 Ganglion. 
 
 p.e. 
 
 Perpendicular ethmoid. 
 
 a?. 11. 
 
 Alinasal. 
 
 il. 
 
 Humerus. 
 
 P9- 
 
 Pterygoid. 
 
 ar. 
 
 Articulare. 
 
 li.s.c. 
 
 Horizontal semicircular canal. 
 
 ph. 
 
 Phalanx . 
 
 al.s. 
 
 Alisphenoid. 
 
 i. 
 
 Intermedium. 
 
 p. ii. 
 
 Prenasal rostrum. 
 
 al.s p. 
 
 Aliseptal. 
 
 i.a.c. 
 
 Interarcticular cartilage. 
 
 pr.i. 
 
 Pre-ilium. 
 
 (i.o. 
 
 Antorbital. 
 
 i.a.p. 
 
 Internal angular process. 
 
 pro. 
 
 Prootic. 
 
 a.s.c. 
 
 Anterior semicircular canal. 
 
 ie. 
 
 Intercentrum. 
 
 pi-.:. 
 
 Pre-zygaphophysis . 
 
 at. 
 
 Atlas. 
 
 i.e. 
 
 Internal carotid foramen. 
 
 p.s. 
 
 Presphenoid. 
 
 a.t.e. 
 
 Anterior tympanic recess. 
 
 Lei. 
 
 Interclavicle. 
 
 p.s.c. 
 
 Posterior semicircular canal 
 
 an. 
 
 Auditory capsule. 
 
 it. 
 
 Ilium. 
 
 pt.i. 
 
 Post-ilium. 
 
 ax. 
 
 Axis. 
 
 i.o.f. 
 
 Inter-orbital fenestra. 
 
 pl.z. 
 
 Post-zygapophysis. 
 
 li.h.br. 
 
 Basi-hyobranchial. 
 
 i.pn. 
 
 Inter-palatine. 
 
 px. 
 
 Premaxilla. 
 
 b.hij. 
 
 Basihyal. 
 
 i.e. 
 
 Interuiedio-radiale. 
 
 g- 
 
 Quadrate. 
 
 1.0. 
 
 Basioccipital. 
 
 isc. 
 
 Ischium. 
 
 >/:/■ 
 
 Quadrato- jugal. 
 
 b.pf/. 
 
 Basipterygoid. 
 
 i.tb. 
 
 Inferior turbinal. 
 
 r. 
 
 Radius. 
 
 br. 
 
 CeratobranoHal. 
 
 i.tr. 
 
 Inter-trabecula. 
 
 r.i.s. 
 
 Rostrum of basispbenoid (= 
 
 b.s. 
 
 Basispbenoid. 
 
 J- 
 
 Jugal. 
 
 
 rostrum of parasphenoid). 
 
 b.t. 
 
 Basitemporal. 
 
 I. 
 
 Lachrymal. 
 
 re. 
 
 Radiale. 
 
 e. 
 
 Centrum and centrale. 
 
 I.e. 
 
 Lachrymal canal. 
 
 r.st. 
 
 Rostral process of sternum. 
 
 c.a. 
 
 Uncinate process. 
 
 l.s.v. 
 
 Lumbo-sacral vertebrae. 
 
 s.aij. 
 
 Supra-angulare. 
 
 ed.v. 
 
 Caudal vertebra. 
 
 in. 
 
 Mouth. 
 
 sc. 
 
 Scapula. 
 
 c.f.c. 
 
 Cranio-facial cleft. 
 
 ink. 
 
 Meckel's cartilage. 
 
 s.n. 
 
 Septum nasi. 
 
 e.liij. 
 
 Cerato-hyal. 
 
 m.st. 
 
 Metasternum. 
 
 s.i.f. 
 
 Sacro-ischiatic fenestra. 
 
 el. 
 
 Clavicle. 
 
 int.e. 
 
 Metacarpal. 
 
 s.o. 
 
 Supra-occipital. 
 
 CO. 
 
 Columella. 
 
 mt.t. 
 
 Metatarsal. 
 
 sp. 
 
 Splenial. 
 
 cp. 
 
 Carpal. 
 
 mx.p. 
 
 Maxillo-palatine. 
 
 sp.o. 
 
 Sphenotic. 
 
 cr. 
 
 Coracoid and cervical rib. 
 
 it. 
 
 Nasal. 
 
 sq. 
 
 Squamosal. 
 
 cr.g. 
 
 Crista galli. 
 
 n.a. 
 
 Neural arch. 
 
 s.r. 
 
 Sacral rib. 
 
 C.tlJ. 
 
 Tympanic cavity. 
 
 lie. 
 
 Notochord. 
 
 s.se. 
 
 Supra-scapula. 
 
 e.n. 
 
 Centralo-ulnare. 
 
 ii. f. 
 
 Nasal floor. 
 
 St. 
 
 Sternum. 
 
 c.v. 
 
 Cervical vertebra?. 
 
 n.px. 
 
 Nasal process of pre-maxil- 
 
 st.k. 
 
 Sternal keel. 
 
 d. 
 
 Dentary. 
 Distal carpal. 
 
 
 lary. 
 
 s.r. 
 
 Sacral vertebra. 
 
 d.c. 
 
 oh.f. 
 
 Obturator fenestra. 
 
 tb. 
 
 Tibial. 
 
 dg. 
 
 d.t. 
 
 Digit. 
 
 oe.e. 
 
 Occipital condyle. 
 
 t.c. 
 
 Tendon-canal. 
 
 Distal tarsal. 
 
 od.p. 
 
 Odontoidprocess. 
 
 te. 
 
 Tibiale. 
 
 d.r. 
 
 Dorsal rib. 
 
 op. 
 
 Opisthotic. 
 
 t.eo. 
 
 Tympanic wing of occipital 
 
 d.s.r. 
 
 Dorso-sacral vertebra?, 
 
 o.s. 
 
 Orbitosphenoid. 
 
 ts 
 
 Tarsal. 
 
 d.v. 
 
 Dorsal vertebra. 
 
 p- 
 
 Parietal. 
 
 it. 
 
 Ulna. 
 
 e.eth. 
 
 Ectoethmoid. 
 
 pa. 
 
 Palatine. 
 
 ue 
 
 Ulnare. 
 
 e.n 
 
 External nostril. 
 
 p.a.p. 
 
 Posterior angular process. 
 
 ii. s.r. 
 
 Uro-saeral vertebra;. 
 
 e.o. 
 
 Exoccipital. 
 
 pa.s 
 
 Parasphenoid. 
 
 v. 
 
 Vomer. 
 
 Eu. 
 
 Eustachian opening. 
 
 ph. 
 
 Pubis. 
 
 v.a 
 
 Vertebral artery. 
 
 f. 
 
 Frontal and femur. 
 
 p. el 
 
 Posterior clinoid process. 
 
 r.b. 
 
 Vestibule. 
 
 fl> 
 
 Fibula. 
 
 pep. 
 
 Postcoracoid process of ster- 
 num. 
 
 
 
RL. IRISH ACAD. 
 
 CUNNINGHAM MEMOIR: VI. Plate 6 . 
 
 W K.farkpr del a rj nat "MP.Paxker lith 
 
 ■.....!■ 
 
 AL C 
 
PLATE VII 
 
 MORPHOLOGY OF THE DUCK AND THE AUK TRIBES. 
 
 ROVAL IIUSE ACADEMY. CUNNINGHAM MEMOIRS, NO. VI. [19"! 
 
122 Cunningham Memoirs. 
 
 EXPLANATION OF PLATE VII. 
 
 Number of 
 Fig. times magnified. 
 
 1 . ~Uria troile ; 2nd stage ; embryo two-thirds ripe ; skeleton ; side view, . 3i diameters. 
 
[For List of Abbreviations used o£l tins Plate, vide over.] 
 
124 
 
 Cunningham Memoirs. 
 
 LIST OF ABBREVIATIONS. 
 
 
 \The Roman 
 
 Numerals indicate Nerves and i 
 
 heir I 
 
 V am in a. .] 
 
 flC. 
 
 Acetabulum. 
 
 fbe. 
 
 Fibulare. 
 
 per. 
 
 Precoracoid. 
 
 ni\ p. 
 
 Acromial process of scapula. 
 
 f.m. 
 
 Foramen magnum. 
 
 p.c.s. 
 
 Pre-costal process of ster- 
 
 ag. 
 
 Annulare. 
 
 /'■■ 
 
 Furcula. 
 
 
 num. 
 
 al.e. 
 
 Aliethmoid. 
 
 9- 
 
 Ganglion. 
 
 p.e. 
 
 Perpendicular ethmoid. 
 
 it Kit. 
 
 Alinasal. 
 
 h. 
 
 Humerus. 
 
 P!l- 
 
 Pterygoid. 
 
 ur. 
 
 Articulare. 
 
 h.s.c. 
 
 Horizontal semicircular canal. 
 
 ph. 
 
 Phalanx. 
 
 aJ.fi. 
 
 Alisphenoid. 
 
 i. 
 
 Intermedium. 
 
 p. ii. 
 
 -Prenasal rostrum. 
 
 ills p. 
 
 Aliseptal. 
 
 i.a.c. 
 
 Interarcticular cartilage. 
 
 pr.i. 
 
 Pre-ilium. 
 
 a.o. 
 
 Antorbital. 
 
 i.n.p. 
 
 Internal angular process. 
 
 pro. 
 
 Prootic. 
 
 il. S.I'. 
 
 Anterior semicircular canal. 
 
 ic. 
 
 Intercenlrum. 
 
 pr.z. 
 
 Pre-zygaphophysis. 
 
 at. 
 
 Atlas. 
 
 i.e. 
 
 Internal carotid foramen. 
 
 p.s. 
 
 Presphenoid. 
 
 n.t.r. 
 
 Anterior tympanic recess. 
 
 i.el. 
 
 Intei'clavicle. 
 
 p.s.e. 
 
 Posterior semicircular canal 
 
 an. 
 
 Auditory capsule. 
 
 il. 
 
 Ilium. 
 
 pt.i. 
 
 Post-ilium. 
 
 ar. 
 
 Axis. 
 
 i.o.f. 
 
 Inter-orbital fenestra. 
 
 pt.z. 
 
 Post- z ygapophysis . 
 
 b.h.br 
 
 Basi- 1 1 yobranchial . 
 
 i.pa. 
 
 Inter-palatine. 
 
 p.r. 
 
 Premaxilla. 
 
 b.hij. 
 
 Basihyal. 
 
 i.r. 
 
 Intermedio-radiale. 
 
 >!■ 
 
 Quadrate. 
 
 b.o. 
 
 Basioocipital. 
 
 ise. 
 
 Ischium. 
 
 'J-J- 
 
 Quadrato-jugal. 
 
 b.pg. 
 
 Basipterygoid. 
 
 i.tb. 
 
 Inferior turbinal. 
 
 r. 
 
 Radius. 
 
 br. 
 
 Ceratoliranchial. 
 
 i.tr. 
 
 Inter-trabecula. 
 
 r.b.s. 
 
 Rostrum of basisphenoid (= 
 
 b.s. 
 
 Basisphenoid. 
 
 J- 
 
 Jugal. 
 
 
 rostrum of parasphenoid). 
 
 b.t. 
 
 Basitemporal. 
 
 1. 
 
 Lachrymal, 
 
 re 
 
 Radiale. 
 
 c. 
 
 Centrum and centrale. 
 
 I.e. 
 
 Lachrymal canal. 
 
 r.st. 
 
 Rostral process of sternum. 
 
 at. 
 
 Uncinate process. 
 
 l.s.v. 
 
 Lumbo-sacral vertebrae . 
 
 s.ag. 
 
 Supra-angulare. 
 
 cd.v. 
 
 Caudal vertebra. 
 
 in. 
 
 Mouth. 
 
 se. 
 
 Scapula. 
 
 c.f.o. 
 
 Cranio-facial cleft. 
 
 ink. 
 
 Meckel's cartilage. 
 
 s.n. 
 
 Septum nasi. 
 
 C.lllJ. 
 
 Cerato-hyal. 
 
 m.st. 
 
 Metastermnn. 
 
 s.i.f. 
 
 Sacro-ischiatic fenestra. 
 
 el. 
 
 Clavicle. 
 
 Illt.C. 
 
 Metacarpal. 
 
 s.o. 
 
 Supra-occipital. 
 
 CO. 
 
 Columella. 
 
 int. t. 
 
 Metatarsal. 
 
 sp. 
 
 Splenial. 
 
 ep. 
 
 Carpal. 
 
 ni.r.p. 
 
 Maxillo-palatine. 
 
 sp.o. 
 
 Spbenotic. 
 
 cr. 
 
 Coracoid and cervical rib. 
 
 it. 
 
 Nasal. 
 
 Sq. 
 
 Squamosal. 
 
 ci-.ij. 
 
 Crista galli. 
 
 ii.ii. 
 
 Neural arch. 
 
 s.r. 
 
 Sacral rib. 
 
 e.ty. 
 
 Tympanic cavity. 
 
 ■lie. 
 
 Notocbord. 
 
 s.se. 
 
 Supra-scapula. 
 
 c.u. 
 
 Centralo-ulnare. 
 
 ,,./. 
 
 Nasal floor. 
 
 St. 
 
 Sternum. 
 
 c.v. 
 
 Cervical vertebra'. 
 
 n.px. 
 
 Nasal process of pro-maxil- 
 
 st.k. 
 
 Sternal keel. 
 
 d. 
 
 Dentary. 
 
 
 lary. 
 
 8.V. 
 
 Sacral vertebra. 
 
 (I.e. 
 
 Distal carpal. 
 
 Clb.f. 
 
 Obturator fenestra. 
 
 til. 
 
 Tibial. 
 
 dg. 
 
 Digit. 
 
 oe.e. 
 
 Occipital condyle. 
 
 t.e. 
 
 Tendon-canal. 
 
 d.t. 
 
 Distal tarsal. 
 
 od.p. 
 
 Odontoidprocess. 
 
 te. 
 
 Tibiale. 
 
 d.r. 
 
 Dorsal rib. 
 
 op. 
 
 Opisthotic, 
 
 t.eo. 
 
 Tympanic wing of occipital 
 
 d.s.v. 
 
 Dorso-sacral vertebra 1 , 
 
 o.s. 
 
 Orbitosphenoid. 
 
 ts. 
 
 Tarsal. 
 
 d.v. 
 
 Dorsal vertebra. 
 
 p. 
 
 Parietal . 
 
 H. 
 
 Ulna. 
 
 e.eth. 
 
 Eetoethuioid. 
 
 pa. 
 
 Palatine. 
 
 lie. 
 
 Ulnare. 
 
 e.ii. 
 
 External nostril. 
 
 p.a.p. 
 
 Posterior angular process. 
 
 n. s.r. 
 
 Uro- sacral vertebrae. 
 
 e.o. 
 
 Exoccipital. 
 
 pa.s. 
 
 Parasphenoid. 
 
 V, 
 
 Vomer. 
 
 En. 
 
 Eustachian opening. 
 
 pb. 
 
 Pubis. 
 
 r.a. 
 
 Vertebral artery. 
 
 /■ 
 
 Frontal and femur. 
 
 p.cL 
 
 Posterior clinoid process. 
 
 r.b. 
 
 Vestibule. 
 
 /*. 
 
 Fibula. 
 
 pep. 
 
 Postcoracoid process of ster- 
 num. 
 
 
 
RL. IRISH ACAD. 
 
 CUNNINGHAM MEMOIR: VI. Plate 7 
 
 \< 
 
 - \ . i \ 
 
 : 1 1 ? \ 
 
 
 
 WK.Pai-kcr d=L ai nat.,M p Parker.lrtli 
 
 
PLATE VIII 
 
 MORPHOLOGY OF THE DUCK AND THE AUK TRIBES. 
 
 KOYAL IRTSH ACADEMY. CUNNINGHAM MEMOIRS, NO. VI. [20] 
 
126 
 
 Cunn ingham Memoirs. 
 
 Fig. 
 
 1. 
 
 2. 
 3. 
 4. 
 
 5. 
 0. 
 7. 
 
 s. 
 
 EXPLANATION OF PLATE VIII. 
 
 Uria troile ; 1st stage; pelvis; lower view, . 
 
 The same ; 3rd stage ; pelvis ; lower view, 
 
 The same ; same object ; upper view, 
 
 The same ; 1st stage ; distal part of leg ; front view 
 
 The same ; same object ; hind view, 
 
 The same ; 3rd stage ; part of leg ; front view, 
 
 The same ; manus of 2nd stage ; inner view, . 
 
 Part of same ; outer view, .... 
 
 9. Cioeronia pusilla ; distal part of wing ; outer view, 
 
 10. The same ; distal part of pollex, . 
 
 11. The same ; distal part of index, . 
 
 12. The same ; proximal part of manus ; inner view, 
 
 13. The same ; part of fig. 9, .... 
 
 Number of 
 times magnified. 
 
 7i diameters. 
 3f diameters. 
 3|- diameters. 
 
 8 diameters. 
 
 8 diameters. 
 3| diameters. 
 7i diameters. 
 1 1 diameters. 
 
 4i diameters. 
 13^ diameters. 
 13i diameters. 
 
 -i} diameters. 
 131 diameters. 
 
[For List of Abbreviations used on this Plate, ride over.] 
 
128 
 
 Cunningham Me 
 
 mioirs. 
 
 LIST OF ABBEEVIATIONS. 
 
 [T/ie Roman Numerals indicate Nerves and their Foramina.'] 
 
 ac. Acetabulum. 
 ae.p. Acromial process of scapula. 
 
 at/. Angulare. 
 al.c. Aliethmoid. 
 al.1i. Alinasal. 
 
 ar. Avticulare. 
 al.s. Alisphenoid. 
 al.sp. Aliseptal. 
 
 a.o. Antorbital. 
 a.s.c. Anterior semicircular canal. 
 
 at. Atlas. 
 a.t.r. Anterior tympanic recess. 
 
 an. Auditory capsule, 
 
 ax. Axis. 
 b.h.br. Basi-hyoljraiicliial. 
 h.luj. Basihyal. 
 
 h.o. Basioccipital. 
 li.pi/. Basipterygoid. 
 
 l/r. Ceratobranchial. 
 
 b.s. Basispbenoid. 
 
 b.t. Basitemporal. 
 
 c. Centrum and centrale. 
 e.a. Uncinate process. 
 
 cd.c. Caudal vertebra. 
 c.f.e. Cranio-facial cleft. 
 e.lii/. Ccratu-hyal. 
 el. Clavicle. 
 co. Columella. 
 cp. Carpal. 
 
 cr. Coracoid and cervical rib. 
 c'r.g. Crista galli. 
 c.ty. Tympanic cavity 
 e.n. Centralo-uluare. 
 i.e. Cervical vertebra;. 
 
 d. Dentary. 
 (I.e. Distal carpal 
 dg. Digit. 
 
 d.t. Distal tarsal. 
 
 d.e. Dorsal rib. 
 d.s.v. Dorso-sacral vertebrae, 
 
 d.v. Dorsal vertebra. 
 e.elh. Ectoetbmoid. 
 
 e.n. External nostril. 
 
 e.o. Exoccipital. 
 
 En. Eustacbian opening. 
 f. Frontal and femur. 
 fb. Fibula. 
 
 fbe. 
 
 .'''■■ 
 
 9- 
 
 h. 
 
 h.s.c. 
 
 i.n.e. 
 i.a.p. 
 
 !('. 
 
 i.e. 
 
 i.cl. 
 
 it. 
 
 i.o.f. 
 
 i.pa. 
 
 i.tb. 
 i.tr. 
 
 J- 
 
 I. 
 
 I.e. 
 
 t.s.i: 
 
 in. 
 
 ink. 
 
 ■in. s(. 
 
 mt.c. 
 
 int. I. 
 
 mx.p. 
 
 ii. 
 
 it. a. 
 
 lie. 
 
 n.f. 
 
 ll.p.r. 
 Ob.f. 
 
 oc.c. 
 
 od.p. 
 
 op. 
 o.s. 
 
 p- 
 
 pa. 
 
 p.a.p. 
 
 pa.s. 
 
 pb. 
 
 p.cl. 
 
 pep. 
 
 Filmlare. 
 
 Foramen magnum. 
 
 Furcula. 
 
 Ganglion. 
 
 Humerus. 
 
 Horizontal semicircular canal. 
 
 Intermedium . 
 
 Interareticular cartilage. 
 
 Internal angular process. 
 
 Intercentrnm. 
 
 Internal carotid foramen. 
 
 Interclaviele. 
 
 Ilium. 
 
 Inter-orbital fenestra. 
 
 Inter-palatine. 
 
 Internredio-radiale. 
 
 Ischium. 
 
 Inferior turbinal. 
 
 Inter-trabecula. 
 
 Jugal. 
 
 Lachrymal. 
 
 Lachrymal canal. 
 
 Lumbo-sacral vertebra'. 
 
 Mouth. 
 
 Meckel's cartilage 
 
 Metasternum. 
 
 Metacarpal. 
 
 Metatarsal. 
 
 Maxillo-palatine. 
 
 Nasal. 
 
 Neural arch. 
 
 Notochord. 
 
 Nasal floor. 
 
 Nasal process of pre-maxil- 
 lary. 
 
 Obturator fenestra. 
 
 Occipital condyle. 
 
 OJontoiJprocess. 
 
 Opistliotic. 
 
 Orbitospheuoid. 
 
 Parietal. 
 
 Palatine. 
 
 Posterior angular process. 
 
 Parasphenoid. 
 
 Pubis. 
 
 Posterior clinoid proi ess. 
 
 Postcoracoid process of ster- 
 num. 
 
 per. Precoracoid. 
 p.c.s. Pre-costal process of ster- 
 num. 
 p.e. Perpendicular ethmoid. 
 pg. Pterygoid. 
 ph. Phalanx. 
 p. n. Prenasal rostrum. 
 pe.i. Pre-ilium. 
 pro. Proutic. 
 j»/'.i.-Pre-zygapbopbysis. 
 p.s. Presphenoid. 
 p. s.c. Posterior semicircular canal. 
 pt.i. Post-ilium. 
 pt.z. Post-zygapopbysis. 
 /'.'■. Premaxilla. 
 
 q. Quadrate. 
 q.j. Quadrato-jugal. 
 /•. Radius. 
 r.b.s. Rostrum of basisphenoid (= 
 rostrum of parasphenoid). 
 re. Radiale. 
 r.st. Rostral process of sternum. 
 s . a ij . S upra-angulare. 
 sc. Scapula. 
 s.u. Septum nasi. 
 s.i.f. Sacro-isehiatic fenestra. 
 s.o. Supra-occipital. 
 sp. Splenial. 
 sp.o. Sphenotic. 
 sq. Squamosal. 
 s.r. Sacral rib. 
 s.sc. Supra-scapula. 
 
 st. Sternum. 
 st.k. Sternal keel. 
 s.e. Sacral vertebra. 
 ll>. Tibial. 
 I.e. Tendon-canal. 
 te. Tibiale. 
 t.ev. Tympanic wing of occipital. 
 ts. Tarsal. 
 a. Ulna. 
 ue. Ulnare. 
 n. s.e. Uro-sa^ral vertebra:. 
 r. Vomer. 
 v.n. Vertebral artery. 
 v.b. Vestibule. 
 
RL. IRISH ACAD. 
 
 CUNNINGHAM MEMOIR: V!, Plate 8 
 
 W.K. Parker, del aAnat.,MP Parker, Lth 
 
 '■■.'..■ 
 
 ALCIL<,r, 
 
RL. IRISH ACAD. 
 
 CUNNINGHAM MEMOIR: VI. Plate 9. 
 
 cLa 
 
 
 
 t 
 
 J 
 
 8 .- eza 
 
 .. 
 
 
 • 
 
 J 
 
 c ! - 
 
 | ||fer v 
 
 12 
 
 I 
 
 i 
 
 - - 
 
 •ni~. _ I - 
 
 ■mi ? 
 
 <•;,._. 
 
 
 13 , 3 
 
 14 
 
 4 
 
 15 
 
 ■«* ? -- a •■' 
 
 x 
 
 m 
 
 
 (V L 1 ' 
 
 ..1 r \ 
 
 ... .:..■• 
 
 ' 
 
PLATE IX. 
 
 MO UP HO LOGY OF THE DUCK AND THE AUK TRIBES. 
 
 HOITAL IRISH AGADE1I¥. CUNNINGHAM MUMOIRS, NO. VI. [21 | 
 
130 
 
 L 'unningham Memoirs. 
 
 EXPLANATION OF PLATE IX. 
 
 Fia 
 
 1. Aha tor da ; 1st stage ; one-third ripe embryo : distal part of wing ; outer 
 
 view, 
 
 2. The same ; part of same object ; inner view, .... 
 
 3. The same ; 2nd stage ; three-quarter ripe embryo distal part of 
 
 inner view, ......... 
 
 ■4. The same ; same object; outer view, .... 
 
 5. The same ; 3rd stage ; nearly ripe embryo proximal part of maims 
 
 view, ......•••• 
 
 6. The same ; same object ; outer view, ..... 
 
 8. The same : 1st stage ; upper part of tarsus ; front view, . 
 
 7. Uriatroile; 3rd stage; distal part of wing ; inner view, 
 
 9. The same ; 3rd stage ; ankle-joint ; front view, 
 
 10. The same ; lower part of same object ; inner view, . 
 
 1 1 . The same ; adult ; distal part of pollex, ..... 
 
 12. The same ; same skeleton ; distal part of index, 
 
 16. \Ga. The same ; head of embryo, one-third ripe ; 1st stage, 
 
 17. The same ; do. do. two-thirds ripe ; 2nd stage, 
 
 18. The same ; do. do. nearly ripe ; 3rd stage, . 
 
 13. Casuarius bennettu ; ripe embryo ; first three vertebras ; upper view, 
 
 14. The same ; same object ; lower view, ...... 
 
 15. The same ; same object; vertical section, ..... 
 
 Number of 
 times magnified. 
 
 15 diameters. 
 15 diameters. 
 
 6 diameters. 
 6 diameters. 
 
 8 diameters. 
 
 8 diameters. 
 
 22i diameters. 
 
 5 diameters. 
 3 J diameters. 
 3f diameters. 
 
 2 diameters. 
 
 2 diameters. 
 li diameters. 
 Natural size. 
 Natural size. 
 
 3 diameters. 
 3 diameters. 
 3 diameters. 
 
[For List or Abbkeviations used on this Plate, vide oyer. 
 
132 
 
 Cunningham Memoirs, 
 
 LIST OF ABBEEVIATIONS. 
 
 {The Roman Numerals indicate Nerres and their Foramina.'] 
 
 ac. Acetabulum. 
 
 ae.p. Acromial process of scapula. 
 
 ag. Angulare. 
 al.e. Aliethmoid. 
 al.ii. Alinasal. 
 
 ar. Articulave. 
 al.s. Alisphenoid. 
 nl up. Aliseptal. 
 
 a.n. Antorbital. 
 a.s.c. Anterior semicircular canal. 
 
 at. Atlas. 
 n.t.r. Anterior tympanic recess. 
 
 an. Auditory capsule. 
 
 fix. Axis. 
 b.h. In: Basi-li y obranchial . 
 b.luj. Basihyal. 
 
 b.o. Basioccipital. 
 b.pg. Basipterygoid. 
 
 br. Ceratobranchial. 
 
 b.s. Basispbenoid. 
 
 b.t. Basitemporal. 
 
 c. Centrum and centrale. 
 at. Uncinate process. 
 
 cd.v. Caudal vertebra. 
 c./.c. Cranio-facial cleft. 
 e.lnj. Cerato-byal. 
 
 cl. Clavicle. 
 
 eo. Columella. 
 
 ep. Carpal. 
 
 er. Coracoid and cervical rib. 
 or.g. Crista galli. 
 c.ty. Tympanic cavity. 
 c.n. Centralo-ulnare. 
 c.v. Cervical vertebree. 
 
 d. Dentary. 
 (I.e. Distal carpal. 
 dg. Digit. 
 
 d.t. Distal tarsal. 
 
 d.r. Dorsal rib. 
 d.s.r. Dorso-sacral vertebras, 
 
 d.r. Dorsal vertebra. 
 e.eth. Ectoetbmoid. 
 
 e.n. External nostril. 
 
 e.o. Exoccipital. 
 
 Eu. Eustachian opening. 
 f. Frontal and femur. 
 fb. Fibula. 
 
 fbc. Fibulare. 
 f.m. Foramen magnum. 
 fe. Furcula. 
 g. Ganglion. 
 it. Humerus. 
 h.s.c. Horizontal semicircular canal. 
 
 i. Intermedium. 
 i.a.e. Interarcticular cartilage. 
 i.ii.p. Internal angular process. 
 ic. Intercentrum. 
 i.e. Internal carotid foramen. 
 i.cl. Interclavicle. 
 it. Ilium. 
 i.o.f. Inter-orbital fenestra. 
 i.pa. Inter-palatine. 
 i.e. Intermedio-radiale. 
 ise. Ischium. 
 i.tb. Inferior turbinal. 
 i.tr. Inter-trabecula. 
 j. Jugal. 
 /. Lachrymal. 
 I.e. Lachrymal canal. 
 l.s.v. Lumbo-sacral vertebra;. 
 in. Mouth. 
 ink. Meckel's cartilage. 
 in. st. Metasternum. 
 mt.e. Metacarpal. 
 int.t. Metatarsal. 
 in.c.p. Maxillo-palatine. 
 a. Xasal. 
 ii.ii. Neural arch. 
 ne. Notochord. 
 ii.f. Nasal floor. 
 n.p.r. Nasal process of pre-maxil- 
 
 lary. 
 ob.f. Obturator fenestra. 
 oc.c. Occipital condyle. 
 u'/./i. Odontoidprocess. 
 up. Opisthotic. 
 o.s. Orbitosphenoid. 
 p. Parietal. 
 pa. Palatine. 
 p. a. p. Posterior angular process. 
 pa.s. Parasphenoid. 
 
 ph. Pubis. 
 p. el. Posterior clinoid process. 
 pe.p. Postcoracoid process of ster- 
 num. 
 
 per. 
 
 Precoracoid. 
 
 p.c.s. 
 
 Pre-costal process of stei 
 
 
 num. 
 
 p.e. 
 
 Perpendicular ethmoid. 
 
 pg- 
 
 Pterygoid. 
 
 ph. 
 
 Phalanx. 
 
 p.n. 
 
 Prenasal rostrum. 
 
 pr.i. 
 
 Pre-ilium. 
 
 pro. 
 
 "Proutic. 
 
 pr.z. 
 
 Pre-zygaphophysis. 
 
 p.s. 
 
 Prespbenoid. 
 
 p.s.e. 
 
 pt.i. 
 
 pl.z. 
 
 p.v. 
 
 1- 
 
 q.j. 
 
 r. 
 r.b.s. 
 
 r.st. 
 
 s.aff. 
 
 se. 
 
 s.n. 
 
 s.i.f. 
 
 s.o. 
 
 sp. 
 
 sp.o. 
 
 sq. 
 
 s.r. 
 
 s.sc. 
 
 St. 
 
 st.k. 
 s.v. 
 
 tb. 
 I.e. 
 
 te. 
 Leo. 
 
 ts. 
 
 ll. 
 
 e.a. 
 e.b. 
 
 Posterior semicircular canal. 
 Post-ilium. 
 Post-zygapophysis. 
 I'remaxilla. 
 Quadrate. 
 Quadrato-jugal. 
 Radius. 
 
 Postrum of basisphenoid (= 
 rostrum of parasphenoid). 
 Radiale. 
 
 Rostral process of sternum. 
 Supra-angulare. 
 Scapula. 
 Septum nasi. 
 Saero-ischiatic fenestra. 
 Supra-occipital. 
 Splenial. 
 Spbenotic. 
 Squamosal. 
 Sacral rib. 
 Supra-scapula. 
 Sternum. 
 Sternal keel. 
 Sacral vertebra. 
 Tibial. 
 
 Tendon-canal. 
 Tibiale. 
 
 Tympanic wing of occipital. 
 Tarsal. 
 Ulna. 
 Ulnare. 
 
 Uro-sacral vertebra;. 
 Vomer. 
 
 Vertebral artery 
 Vestibule. 
 
NOVEMBER, 1890.] 
 
 ROYAL IRISH ACADEMY. 
 
 «n 
 
 CUNNINGHAM MEMOIRS. 
 
 >J 
 
 No. VI. 
 
 ON THE MORPHOLOGY 
 
 OF 
 
 THE DUCK AND THE AUK TRIBES. 
 
 BY 
 
 W. KITCHEN PARKER, F.R.S. 
 
 mm Mint llai.es. 
 
 DUBLIN: 
 
 PUBLISHED BY THE ACADEMY, 
 AT THE ACADEMY HOUSE, 19, DAWSON-STEEET 
 
 SOLD ALSO Br 
 
 HODGES, FIGGIS, & CO., GRAFTON-STREET. 
 
 And bt WILLIAMS & NOEGATE, 
 LONDON : 
 14, Henrietta-street, Covent Garden. 
 
 1890. 
 
 EDINBURGH : 
 
 20, South Frederick- street. 
 
 PRICE FIVE SHILLINGS AND SIXPENCE. 
 
CUNNINGHAM MEMOIRS." 
 
 Price to the Public. 
 
 £ s. d. 
 
 jic Transformations. By John Casey, LL.D., F. B. S., V. P. E.I. A., Professor of 
 
 higher Mathematics and Mathematical Physics in the Catholic University of Ireland, .060 
 
 ,4 Lumbar Curve in Man and the Apes, -with an Account of the Topographical Anatomy of 
 
 the Chimpanzee, Orang-utan, and Gibbon. By D. J. Cunningham (Edinb. & Dubl.), 
 
 M.E.I. A., Professsor of Anatomy and Chirurgery in the University of Dublin. (With 
 
 Thirteen Plates), 090 
 
 3. — New Eesearches on Sunheat, Terrestrial Eadiation, &c. By Eev. Samuel Haughton, M.A., 
 M.D., Dubl. ; D.C.L., Oxon. ; LL.D., Cantab. & Edin. ; Senior Fellow of Trinity College, 
 Dublin. (With Nine Plates), 050 
 
 4. — Dynamics and Modern Geometry: A New Chapter in the Theory of Screws. By Sir Eobeet 
 
 S. Ball, LL.D., F.E.S., Eoyal Astronomer of Ireland, .020 
 
 5. — The Eed Stars : Observations and Catalogue. By J. Birmingham. New Edition by Eev. 
 
 T. E. Espin, B.A., F.E.A.S., 080 
 
 6. — On the Morphology of the Duck Tribe {Anatidce) and the Auk Tribe {Alcida). By W. Kitchen 
 
 Parker, F.E.S. (With Nine Plates), 5 6 
 
 TRANSACTIONS. 
 
 Quarto, boards ; or in Parts, stitched. 
 
 Vols. I. to XXIII. {some out of print). For Prices, &c, inquire at the Academy. 
 
 Vol. XXIV. — Science (complete), 31s. 6d. 
 
 Polite Literature (complete), 5s. ) 
 
 , v , Together (with Title), 24s. 
 
 ,, Antiquities (complete), 19s. 6a. ) 
 
 Vol. XXV.— Science (complete), 37s. 6d. Vol. XXVI.— Science (complete), 35s. 
 
 Vol. XXVII. — Polite Literature and Antiquities (complete), 17s. 
 
 Vol. XXVIII.— Science (complete), 43s. 
 
 Vol. XXIX. — In progress of publication. 
 
 For further details inquire at the Eoyal Irish Academy House, 19, Dawson-street, Dublin. 
 
DUBLIN : 
 
 Printed at the University Press, by PONSONBT & WELDPJCK, Printers to the Royal Irish Academy. 
 
UNIVERSITY OF ILLINOIS URBANA 
 Q 598 4P220 C001 
 
 ON THE MORPHOLOGY OF THE OUCH AND THE AU 
 
 3 0112 010232665 
 
."-.:'" ■: :. -.'" M^W:?>