Glow or viwgl.( 89379 1817 ARTES SCIENTIA LIBRARY VERITAS OF THE UNIVERSITY OF MICHIGAN UNUM LE PLURIBUS U TUEROR SI QUERIS PENINSULAM-AMOENAM CIRCUMSPICE LUDO.B.I.W.99 . MUSEUM Museums QA 667 613 2893 12 DIVISION OF HERPETOLOGY INDIAN SNAKES. oo AN ELEMENTARY TREATISE ON OPHIOLOGY WITH A DESCRIPTIVE CATALOGUE OF THE SNAKES FOUND IN INDIA AND THE ADJOINING COUNTRIES. BY EDWARD NICHOLSON, Surgeon, Army Medical Department. SECOND EDITION REPRINTED. MAD RAS: HIGGINBOTHAM AND CO. By Appointment in India to His Royal Highness the Prince of Wales. 1893. QL 66/ .N63 1893 MADRAS: PRINTRD BY HIGGINBOTHAM AND CO., 1 2 & 165, MOUNT ROA1). 164, 164 J.it 13/8/99 PRE FACE. be 6-12-20 The First Edition of this treatise was published under the disadvantageous circumstances of my being stationed in Burma at the time. Since my return to the Madras Pre- sidency I have had but little leisure for collecting further materials and I had expected that some abler hand than mine would have taken up the subject. But as my very elementary treatise remains the only Manual of Indian Ophiology available, I have determined to diminish as much as possible the imperfections of my first attempt at famili- arizing English residents in India with an interesting branch of zoology, and at clearing away the haze of fiction which still obscures it. In carrying out this purpose I have been seconded by the enterprise of the publishers; the remainder of the first edition has been withdrawn in order to make way for the present revised issue. Whilst I have endeavoured to render this treatise as complete as possible for non-scientific readers, those desirous of studying the subject thoroughly will, I hope, find it an efficient introduction to the zoological and medical literature of the subject. The student should certainly follow up this introduction to Dr. GUNTHER's splendid work on the Reptiles of British India, and, if desirous of extending his information, he may consult with advantage the following books :-Professor Owen's Comparative Anatomy and Physiology of Vertebrates, (first volume); SCHLEGEL's Essai sur la Physionomie des Serpents, (La Haye, 1837); GERARD KREFFT's Snakes of Australia, (Sydney and London, 1869) ; 0. PREFACE. Major BEDDOME's papers in the Madras Journal of Medical Science ; Mr. THEOBALD's papers in the Journal of the Linnean Society and that of the Asiatic Society of Bengal. In the latter Society's Journal and in the Annals and Magazine of Natural History a mass of ophiological infor- mation is scattered. I cannot omit to mention RUSSELL'S Account of Indian Serpents, 1796 ; however antique and unfitted for the guidance of the student, it will always be of interest as the work of a pioneer in Indian zoology. The First Edition of this Manual was sadly deficient in illustrations. This has been repaired by the addition of plates, which in every case reproduce drawings taken by me from specimens or dissections. As illustrative of the physio- logical part and aiding in the recognition of the principal kinds of snakes, I trust that they will be found to answer their purpose. E. N. BANGALORE, April 1874. CONTENTS. 06.10 6. PAGE. INTRODUCTION. Place in the Animal kingdom VII PART I.-PHYSIOLOGY. CHAPTER I.-The Skeleton... 1 11.-The Mouth and Teeth of harmless snakes...... 5 III.--The Mouth and Teeth of venomous snakes 9 IV.-Internal organs.. 19 V.The Senses.... 23 VI.--The Integuments 24 PART II---CLASSIFICATION. CHAPTER I.--Principles 36 II.-Diagnosis of an unknown snake and method of description 44 III.-Descriptive Catalogue of Indian snakes.......... 46 PART III.-NATURAL HISTORY. CHAPTER 1.--The Snake at liberty 125 II.-The Serpentarium 131 III. The Museum 139 IV.-Snake-poison and antidotes 144 V.-Schemes of extermination 161 VI.-Snake mythology...... 165 ALPHABETICAL INDEX TO THE DESCRIPTIVE CATALOGUE 177 . . . . teo An Index of Anglo-Indian, Hindustani, Tamil and Burmese names will be found at page ... 133 INTRODUCTION. PLACE IN THE ANIMAL KINGDOM. SUB-KINGDOM.-VERTEBRATA. Section (Huxley). Class. Order. Pisces. Ichthyopsida. Amphibia. r 1.-CHELONIA, Tortoises. II.-OPHIDIA, Snakes. [Reptilia. { III.—LACERTILIA, Lizards. Sauropsida...... 3 IV.---CROCODILIA, Crocodiles.* and five extinct orders. Aves. Mammalia. Mammalia. The division of zoology, which treats of reptiles, is called herpetology; the sub-division devoted to snakes only is called ophiology. be thus defined :- Reptiles of very elongate body, without limbs or with rudimentary hind limbs scarcely visible from without; pro- gressing by means of abdominal plates moved by numerous ribs. The jaws, especially the lower, capable of extensive movement and great expansion ; both jaws and palate generally bearing teeth. The external ear absent. The eye unprotected by eyelids. The integument scaly, and the epidermis cast at frequent intervals. Some kinds of snakes possess perforated or grooved teeth conveying a poisonous salivary secretion into the system of animals bitten by them. Snakes may * Crocodiles differ from lizards by possessing a sternum or breast bone. ORDER OF THE PLATES. PLATE I ... to face page 4 . . . II 6 . . OOO ... 9 9 III 12 ... ... IV 14 e. . ... .. 99 V 22 99 VI 32 ... 99 VII 48 - VIII 50 ... وو IX 52 ... ... X 62 99 XI 68 . 99 XII 82 ... وو XIII 86 . .. XIV 90 ... . . ... XV 94 ... XVI 98 .. 9 XVII 104 99 XVIII 106 1 .. ... ... 9 XIX 110 . .. ... 99 XX 124 O. ... . 97 PART I.-PHYSIOLOGY. CHAPTER 1.-THE SKELETON. The bony parts of the snake consist of a skull, a long vertebral column and ribs. The vertebræ are very numerous, varying from about 120 to upwards of 400 in the body; those of the tail number from 4 or 5 in some burrowing snakes to as many as 200 in certain tree snakes, in no case exceeding the dorsal vertebræ in number.* The vertebræ, Plate I, figs. 2 and 3, are procoelous, i.e., the bodies are articu- lated by ball and socket joints, the socket being in front of the body; the movement of each joint is limited by other minor joints between the adjacent 'apophyses' (or protuberances) of each pair of vertebræ; but, as a whole, the vertebral column is capable of extensive motion in every direction. Of the numerous apophyses the most obvious are the posterior or 'neural spine and the anterior spine or 'hypapophysis. The neural spines are most prominent in some venomous snakes; in Bungarus fasciatus they are unusually large and are firmly connected with the skin. The anterior spines are susceptible of a peculiar modifica- tion; in the genera Elachistodon (India) and Dasypeltis (Africa) those of the cervical vertebræ penetrate the gullet and act as pharyngeal teeth; several of them are tipped with dental crust. * There may possibly be exceptions. I have found a specimen of the common green tree-snake to have 172 dorsal and 169 caudal vertebræ, the tail being four-tenths of the entire length. 2 All the cervical and dorsal vertebræ,* excepting the first two of the former, support ribs. Each pair of ribs rakes backwards, and then bending towards the median line terminates in two cartilaginous filaments attached to the ventral ‘scute' or shield. The ‘hemal' arch is incomplete, the pair of ribs being connected anteriorly by integumen- tary tissue only. The ventral shield connected with each pair of ribs is an organ of locomotion, and the numerous shields arranged in clincher work act as legs when alter- nately raised and depressed by the muscles of the ribs. The snake uses these organs in different ways; when moving slowly a vermicular action along the ribs causes the ventral shields to catch the ground in succession and the means of progress is nearly imperceptible; but rapid movement is effected by the alternate contraction of a part of the muscles of either side throwing the body into an S form; at each curve one side of the ventral shields holding the ground while the other side advances. These movements are not done with any visible alternation, but in a progres- sive and undulating manner of considerable gracefulness. When turning round slowly, the movement becomes a kind of counter-marching, where every pair of ribs has to come up to the pivot point before proceeding in the opposite direction. In case of alarm, these movements become more sudden, the snake throws itself into sharp curves, and a jerking motion of the body changes the ordinary imper- ceptible gliding motion into a rapid series of wriggles. Obstacles to other animals are rather favourable to the pro- gress of snakes; whilst they are powerless on a smooth surface, roughness aids them considerably; a stone, a root or a twig becomes a fulcrum for the anterior parts of the body, and brings the posterior parts rapidly up, so that the ground * There is no real distinction between dorsal and cervical vertebræ, the latter term is not, therefore, to be taken in a strict anatomical sense. 3 most favourable for the snake to pursue or retreat is the least favourable to his prey or his pursuers. In a few genera of venomous snakes, Naga (the cobra) and Ophiophagus (the hamadryad) especially, the cervical ribs are elongated and capable of erection from their usual supine state so much as to stretch the skin of the neck into a broad flat disk. Three families of Indian snakes, Tortricidoe, Pythonidoe, Erycido, have rudimentary hind limbs. Each limb consists of a claw or spur protruding from a groove on either side of the anus, and internally of two small bones, which may be called the tibia and the tarsus. These relics of a former stage of development can hardly be of any use for progres- sion; it has been thought that they were of use as auxiliary sexual organs, and this opinion is strengthened by the fact that in Gongylophis conicus one of the Erycidæ, I find that the male alone is provided with them. In five adult females which I dissected there was no trace of them; the only adult male specimen I have is well-spurred. The skull is elongated and of somewhat oval shape, being rounded behind the jaws and tapering at the muzzle. Its broadest part is just behind the eye, where it expands above on either side to form the postfrontal bone the posterior bony ring of the orbit; the anterior limit of the orbit is formed by a similar bony process, the prefrontal bone, and it is bounded below by the maxillary and by the palate bone. This part of the head is nearly entirely occupied by the orbital cavities, which in the median line are only separated by the descending plates of the frontal bones. The bones of the ophidian skull, exclusive of the maxillary and mandibular arches, I shall merely mention, leaving the comparative anatomist to study them in the pages of Owen. 4 Basioccipital, exoccipitals, and super- occipital, forming the walls Basisphenoid and presphenoid, ali- ( of the skull. sphenoids, Mastoids, 1.* Parietal, 2. Frontals, 3, postfrontals, 4, prefrontals and lacrymals, 5. Vomer, nasals, 6, and turbinals, t. The maxillary arch is composed of the following bones :- The premaxillary, 7, a small bone wedged in the nasal interspace and, except in the Pythonidoe, not bearing teeth. The maxillaries, 8, one on each side, of very variable shape. The palatines, 9, one on each side, lie parallel to the maxillaries between them; they bear teeth except in Oligodon and some earth snakes. The pterygoid, 10, and ectopterygoid, 11, of each side form a Kshaped bone (the ectopterygoid being represented by the thin stroke) they abut against the posterior extremities of the palatine and maxillary respectively, com- municating motion to them. The pterygoid bears teeth continuously with the palatine row; its posterior end is loosely connected with the tympano-mandibular joint. The mandibular arch comprises the following: The mandibles or lower jaw bones, 12, connected at the chin by the geneial muscles and skin only. Each mandible is composed of two principal parts, the articular posteriorly and the dentary in front; these are connected by a wedge- shaped suture at the back of the row of teeth. The articular * The figures refer to Plate I, figs. 1 and 2. PLATE I. മ്മൾ മ 10 71 10 1 71 bouch front 10 Aside 2 ہے۔ 3 back side a sonra 99 Figs. 1 & 2. Skull of Ptyas mucosus, (Colubrido), harmless. 1 (Right fig.) Skull from above. 5 (Left fig.) below. 2 Skull from the side; views of a vertebra. Fig. 3. Skull of Bungarus fasciatus, (Elapidce), venomous. Fig. 4. Naga Tripudians, (Elapidoe), venomous. Fig. 5. Daboia elegans, (Viperide), venomous. INIL OF Rich 5 portion bears a deep cavity for the insertion of the temporal muscles; in the vipers a thin plate rises on the inner side of this cavity. Close to its posterior end the mandible articulates with the tympanic bone, 13. In the harmless snakes this is short and stout, in the venomous snakes it becomes long and slender. Its upper extremity is suspended from the mastoid, a partly detached bone of the skull. Owing to the loose connection of the mandibles at the chin, and to there being three joints connecting successively the mandible, the tympanic and the mastoid to the skull, the lower jaws have an extensive range of motion both per- pendicularly and horizontally, and are also to a certain extent independent of one another. The maxillary and palatine of either side being also loosely connected to the base of the skull are capable of being pushed forward or retracted by the pterygoid bones, themselves loosely attached posteriorly. Each of the four half-jaws being then capable of independent motion a snake is able to advance them one at a time, the prey he is swallowing being securely held by the other three. Also, the action of the pterygoid bones being to push forward the maxillary and palatine, if either of these be fixed at one point, the to and fro motion will become converted into a circular motion with the point of attachment as a centre. This is the principle on which the poison-fang is erected in venomous snakes. CHAPTER II.--THE MOUTH AND TEETH OF HARMLESS SNAKES. THE The gape of the mouth is very considerable and, owing to the multiplication of joints between the skull and the mandibles, the upper and lower jaws can be separated until they form nearly a straight line. The mouth is never opened except for the purpose of seizing prey or in defence or sometimes in yawning, after food or drink; a chink in 6 the rostral shield permits the slender-forked tongue to dart in and out with a rapid quivering motion. On separating the upper and lower jaws, one cannot fail to be struck with the exact fit of these two parts. Every relief on one surface fits into a corresponding depression on the other surface, and accurate apposition of every part is obtained. The roof of the mouth is divided into three parts by the four rows of teeth (Plate II.) These three depressions receive the three prominences of the lower jaw, on each side the mandi- bular teeth, in the middle the windpipe. The prehensile apparatus is thus composed, on each side, of a row of lower teeth fitting between two rows of upper teeth ; the middle space being occupied by the windpipe, or rather its upper extremity, the larynx. This, however, only occupies the two posterior thirds of the middle space, as the anterior third is occupied, above by the nasal fossæ the floor of which forms a low fore-palate, below by the sheath of the tongue. The posterior aperture of the nasal fossæ is there- fore just in front of the aperture of the larynx (the glottis) and air passes in a straight course from the nostrils to the windpipe. Beneath the skin of the lips, especially at the angle of the upper jaw, are numerous small salivary glands, but their orifices are too small to be detected. The salivary glands extend along the dentary portions of both jaws and transude their contents through small orifices within the mucous fold surrounding each tooth.* They are usually four in number on each side, the maxillary, mandi- bular, lacrymal, and nasal, but their size and disposition vary considerably. The latter two supply the palatine and pterygoid teeth with saliva, but the lacrymal, according to Cloquet, furnishes also the small quantity of lubricating fluid required between the eyeball and is epidermal covering. Every Indian snake, except the genus Oligodon and some * Such is my impression both from dissection and from analogy. PLATE II. 2. e z... -- ههههههد 3 02 eeee 59 f ماهفيد 7 6 Fig. 2. 99 Mouth and teeth of harmless snakes. Fig. 1. Ptyas mucosus; gape of the jaws. superficial dissection of the jaws; the dotted parts are salivary glands. Fig. 3. deep dissection. Fig. 4. showing palate and pterygoid regions. Fig. 5. Passerita mycterizans. Fig. 6. Simotes bicatenatus. Fig. 7. Lycodon aulicus; superficial dissection. 99 99 92 99 ONE 3, OF H. c 7. of the small burrowing snakes, has six rows of teeth. Of these, two are on the maxillaries (and occasionally on their posterior continuations the ectopterygoids), two run parallel to these along their inner side, on the pterygo-palatine lines of bones; the other two are the mandibular teeth in the lower jaw. The pterygopalatine row of teeth is always the longest the maxillary row is shorter. The former row may contain from ten to thirty teeth, the latter from five to twenty or more; the mandibular row is nearly equal in number to the maxillary. It is by no means easy to determine the number of teeth possessed by a snake owing to their non-permanent charac- ter and to the difficulty in distinguishing the new from the old. Some snakes have teeth of equal or nearly equal size (isodont) whilst in other kinds the teeth are irregular, or gradually increase or decrease from before hindwards. A very common form of dentition is for the teeth to increase gradually and to terminate by a long tooth at the hinder end of the maxilla (coryphodont.) These teeth are all directed more or less backwards, and oppose a formidable obstacle to any resistance on the part of prey once seized; they are composed of a horny sub- stance impregnated with bone-earth, formed originally on a vascular centre, hollow in structure, and in the form of an elongated cone, curved backwards at the base. Each tooth springs from a dental matrix in the bone, protected externally by a mucous envelope ; the greater portion of the tooth is concealed by this envelope which is however sufficiently loose to offer no resistance to the use of the teeth. Inside this fold will be found a number of other 8 teeth in a more or less advanced state, each of which will in its turn become fixed to the bone, by the successive shed- ding of its predecessors. ... The jaws are moved by the following muscles : Action. 1. Masseter(superficial temporal),a..Flexor of the mandible. 2. Temporal (deep), 6......... do. 3. Posttemporal, C...... do. 4. Tympano-mandibular, d............ Extensor of the mandible. 5. Costo andneuro-mandibular, e.... do. 6. Ectopterygoid, f........ Depressor of the maxillary. 7. Entopterygoid, g........ do. 8. Postfrontopterygoid, h.............Erector of the maxillary. 9. Presphenopterygoid, i.............. do. 10. Presphenopalatine, j..... Depressor of the maxillary. 11. Presphenovomerine, k.......... Depressor of the premaxillary 12. Intermandibulary, l........ Attractor of the mandibles. 13. Masto-tympanic Levator tympanici and ex- tensor of the mandible. 14. Basispheno-tympanic .Depressor tympanici and at- tractor of the mandible. 15. Trachelo-tympanic Extensor of the mandible. . ... Besides the primary actions given above, these muscles have secondary actions in the attraction and devarication of the mandibles, &c. No written description of these muscles will convey such a good idea of their situation and action as the figures in Plates II, III and IV. I would only make a few remarks on those which cannot well be figured. The prespheno- vomerine is a thin tendinous muscle passing along the roof of the mouth. The masto-tympanic is by no means easy of discovery, and the basispheno-tympanic is, as a rule, only to be found in venomous snakes. The muscle which I have given as trachelo-tympanic is the trachelo-mastoid of Owen, but as I always find it inserted into the tympanic, I prefer І the former name. 9 a On removing the skin from the cheek and lips of a harm- less snake the first structure to be observed is the long ligament leading from the back of the maxillary to the tympano-mandibular articulation ; this ligament is in reality formed by a thickening of the fascia covering the temporal muscles. These muscles are the superficial and posterior temporalmuscles and the tympano-mandibular; on removing them the deep temporal is seen, its two heads divided by the maxillary nerve. The large lacrymal gland is also exposed on removal of the superficial muscles. The maxillary is suspended posteriorly by the jugal ligament (a structure corresponding perhaps to the zygoma in man) to the postfrontal bone; in venomous snakes this ligament becomes of considerable importance. The muscles of the palato-pterygoid region are covered by the rugate mucous membrane of the mouth and pharynx; on removing this, we expose the muscles, and also, between the palatine and maxillary rows of teeth, the floor of the orbit; in this space the maxillary vessels are seen. CHAPTER III.---THE MOUTH AND TEETH OF VENOMOUS SNAKES. To the disciple of Darwin the modifications we are about to study have been developed by natural selection. Several harmless snakes have long simple fangs for the purpose of holding tough-skinned prey, others, including nearly all the tree-snakes, have grooved fangs, though, as far as we know, without any modification in the quality of the saliva. With these facts before us, and with the knowledge that in some animals the saliva becomes poisonous under certain conditions, there can be little difficulty in accounting for the development of the most perfect poison-apparatus. Neither in the fangs, in their mucous envelopes, in their 2 10 erector muscles, in the poison gland, is there any new or special organ ; in each case there is a clearly marked grada- tion of development.* Roughly speaking there are four stages in the develop- ment of poison apparatus :- 1°. The presence of grooved fangs in snakes which are either unprovided with poisonous saliva or whose venomous quality is so slight that its effect has not been observed.t (Nearly all the tree-snakes; the fresh water snakes.) 2º. The possession of a salivary gland secreting poison and of a grooved tooth in front of the other maxillary teeth. Little modification in the shape or mobility of the maxillary. (The Sea snakes Hydrophida, and the Elapide of Aus- tralia). 3º. The Maxillary is shortened, it contains one fang with a perfect canal, and often one or two simple teeth behind the fang. It possesses a degree of mobility sufficient to raise the fang from a semi-erect to a nearly perfectly erect position ; the angle moved through being less than 45º. (The Indian Elapidce). 4º. The maxilla is higher than it is long, and contains only one tooth, a fang several times its own length. It is very * I am well aware that my opinion is by no means general; indeed I may say that I have not seen it mentioned by other naturalists; but this I ascribe to the maze of errors in which our ideas on snakes have so long been enveloped, to the fascination which the marvellous still has, and the few opportunities possessed by European zootomists for investigating the subject. I earnestly beg the medical profession in India to study this subject by dissection of different snakes; there is a distressing absence of information and our text books of com- parative Anatomy are all but silent on these points to which the hypothesis of Darwin gives especial importance. of These snakes have by some naturalists been classed as the section Suspecta between the sections Innocua and Venenosa. 11 mobile and, when pushed forward by the ectopterygoid, the fang usually lying supine becomes perfectly erect, the angle moved through being little short of 90°. (The Viperina). These stages of development are far from being abrupt; when the fauna of Australia is taken into consideration, we find steps between them, both as regards development of maxillary and fangs, and degree of venomous quality. The poison apparatus is best studied in the large and well developed examples afforded by the cobra and the chain-viper. On examining the mouth of the cobra, dis- sections of which are given in Plate III, the peculiarities to be remarked are-the gingival envelope of the fang, the depression in the lower lip for the reception of the fang when the mouth is shut, and the absence of any teeth (except a rudimentary one) behind the fang. Slit up this gingival fold and the fang will then be exposed; it will be seen to be fixed in very much the same position as a dog's fang, though curving more backwards, and to fit into a depression in the lower lip. Now dissect the skin off the cheek of the cobra, from the nostril in front to the angle of the mouth behind. A large flask-shaped gland will be exposed on the cheek, extending for half an inch or more behind the eye; it is continued by a duct along the lower edge of the orbit as far forwards as the nostril; a dense fibrous sheath covers the gland and forms a point of attach- ment to fibres of the temporal muscles. Cut through the duct at its beginning, just behind the eye, and a canal of very small calibre will be seen in its axis ; pass a fine bristle down the canal, and by careful manipulation this probe will be seen to go to the end of the maxilla, turn down- wards over it, and enter the mouth inside the gingival envelope of the fang, and in front of an orifice in the base of the fang. This examination requires careful dissecting 12 and skilful manipulation in the Elapidæ, but in the vipers the arrangement is on a larger scale and much easier of demonstration. If we now dissect away the soft parts and expose the maxillary, we shall see a great modification in its form com- pared with the normal type. It barely reaches as far back as the hinder part of the orbit, its shortness being compen- sated by increased length of the ectopterygoid. A short tooth is found at its hinder part, but this is rarely percep- tible until dissected down to, and appears to be rudimentary. The shape of the maxillary resembles that of a comma the open space protected by the thin curved part being occupied by the matrix of the fang; the thick part in front bears the fang. This part of the bone is thick and wide, and it bears, side by side, depressions for two fangs; one, the outer socket, is generally occupied by the fang in use, the other by the fang in course of growth. When the fang in use has only recently set it may be found to occupy the inner socket, whilst the outer socket, from which the old fang has just fallen is vacant, and remains so until the new fang has worked its way outwards. Sometimes these two fangs are found perfect at the same time, then one of them, generally the outer or old fang, will be loose. This occurs at the time . of casting the skin, and I have several times removed the old fangs easily with the finger and thumb or a small forceps. The fang is slightly curved backwards and inserted at an angle so as to form a hook in the jaw. It is in shape like a short elephant-tusk and does not exceed 28-hundredths of an inch in the longest specimen I have seen. In struc- ture it differs from other teeth in having, when fixed, two orifices communicating with the interior. The pulp cavity is atrophied, and in front of it there is a complete canal. Both orifices of this canal are in front, the upper close to and forming part of the base, the lower at a distance from PLATE III. a O :) c 3 2 6 luro { a. 99 5 # Anatomy of the jaws of the cobra. Fig. 1. Gape of the jaws. Fig. 2. Superficial muscles and poison gland. Fig. 3. Deep muscles, the glands removed. Fig. 4. Palate and pterygoid muscles. Fig. 5. Base of the skull. Fig. 6. Poison fang of the cobra. a. Back view. part of the outer layer removed. 7. Front view. c. Section, enlarged. Fig. 7. Poison fang of the Daboia viper. M y 13 the point equal to about one-tenth of the length of the fang; a groove connects the orifices, or rather did connect them during the growth of the fang, at which time the canal, originally open in its entire length, became closed. The canal only occupies the front of the fang; the hinder part is a bony columu giving considerable strength to the structure. In the Viperine snakes a transition takes place, gradu- ally culminating in the most perfect form of poison- apparatus, viz., a long fang usually lying supine along the jaw, but capable of full erection. The genus Trime- surus is not nearly so complete as this, the fang is long, but the erection imperfect; the maxillary consists of an open shell communicating with the exterior of the cheek and forming the pit characteristic of the crotaline snakes. But it is in Daboia that we see the perfection of mechanism ; on removal of the skin covering the cheek, we come at once across the strong jugal ligament lying below the eye; it binds the upper part of the maxillary to the prefrontal and postfrontal bones, thus affording a fulcrum for the action of the erectile apparatus. The maxilla is found to be con- siderably modified in form ; it is no longer placed below the orbit, this position is occupied by the elongated ecto- pterygoid, whilst the maxillary, only one-fifth of an inch long (in a large Daboia) but double that in height, is placed at the end of this bone like a hammer-head at the end of its handle. Imagine a hammer-head with the claw downwards (repre- senting the fang,) and hinged at its junction with the handle (the ectopterygoid bone). Now if the top of the hammer- head be fixed by a ligament to a fulcrum, protrusion or retraction of the handle will cause the claw to be either erected or depressed. The muscles by which the ectopterygoid bone is thus a 14 moved forwards in order to erect the maxillary and fang are the same as those which move the ectopterygoid and maxil- lary bones in harmless snakes while swallowing their prey. The action is principally effected by the postfrontopterygoid and presphenopterygoid muscles (h and i in the plates) and these are antagonized by the ectopterygoid, entopterygoid and presphenopalatine muscles, f, g and j. In the vipers the fang is much longer than in the cobra and other Elapidoe, but its length has been greatly exagge- rated, as it rarely exceeds half an inch in the largest species. It is however so long that it cannot, as in the Elapido, be received semi-erect into a pit in the lower lip; hence the necessity for its complete depression when the mouth is shut. This is effected by the aid of a slip of the ecto- pterygoid muscle passing to the mucous envelope. The tube of the fang is also of larger calibre and the poison duct is plainly seen to open into the mouth just in front of the basal orifice; the duct winds round a groove in the surface of the maxillary, (Plate IV) and a bristle passed along its canal, from behind forwards, will be seen to pass out by the orifice at the base of the mucous envelope of the fang: The mechanism of the bite of a poisonous snake may differ somewhat in the viperine families from that usual with the Elapido. The cobra bites just as a dog does, the re-curved position of the fangs rendering a slip impos- sible; whilst the vipers, though biting also, are able to strike sideways with their long erected fangs. In either case the effect is the same, though a bite will be much more effectual than a mere prick without any counterpressure from the lower jaw. The mucous envelope of the fang is mechani- cally puckered up, and by its contraction forces the poison- , ous saliva, as it issues from the duct, to flow into the canal of the fang by its basal orifice. Muscular pressure and spasmodic action of the glaud cause an ejection of poison PLATE IV. \ a a 5 1 کیا 0 2 3 Host f 5 6 Daboia elegans, (Viperido). Dissections of the head. الامام Fig. 1. a. Skin and part of gingival envelope removed. b. Poison gland exposed. c. Lacrymal gland exposed. Fig. 2. Deep dissection. Fig. 3. Palate and pterygoid muscles. Figs. 4, 5 & 6. Skull from above, below, and left side. GNL OF " M ICH 15 into the fang and through it into the wound. But if there be no obstacle to pucker up the mucous envelope, then the poisonous saliva finds its way into the mouth just like the saliva of the other glands, running down the inside of the gingival fold along the outer surface of the fang. I have seen the saliva ejected by an enraged cobra in quantities which could not have passed through the fang, for experi- ments enable me to affirm that a cobra could not inject through the fang with more force than would be vecessary to expel one drop (a mivim) in three seconds, so fine is the inferior orifice of the fang. A viper, however, could inject the same quantity in half a second, and fluid may be forced through its fang in a fine stream, whilst small single drop- lets can alone be ejected from the cobra’s fang: The poison of the venomous snakes is secreted by the large parotid gland. But a curious observation has been made by Mayer and corroborated by Mr. Stolicska of the Indian Geological Survey, that a species of Callophis (C. intestinalis) has supplementary poison glands in the thoracic cavity; they extend one-third down the body, keep- ing close to the gullet on the ventral side, and reach as far as the heart where they are thicker than above. I am not aware, however, of any experiments as to the character of , the secretion furnished by this gland. I suspect it is a salivary gland to the gullet. There is no difficulty in forcing a venomous snake to yield the poison accumulated in the parotid glands. Pressure on the glands while the fangs are erected over the edge of a watch-glass will cause a flow of the saliva, generally in large drops from between the fang and the mucous envelope, more rarely in a fine jet from the apical orifice of the fang. This is a viscous yellowish fluid, of faintly acid : re-action; exposed to the air it dries rapidly, the film cracking all over and thus separating into yellow crystals not unlike a 16 Do. do. 4.7 do. 66 do. do. 2 do. those of santonine. The crystalline form is only apparent, it is analogous to that of the various pharmaceutical citrates of iron, which though uncrystallizable appear to be crystal- live from the solution having beenevaporated on glass plates. A recently captured cobra will yield from six to twenty grains weight of poison, the quantity being greatest in wet weather ; the crystalline residue is from twenty to sixty-six per cent. on the fluid poison. The following extremes and average were obtained in the course of some huudreds of experiments : A cobra gave 8 grains of poison, yielding 1.6 grains residue. 7 do. Do. 22 Average quantities 6 When being brushed off the watch-glass on which it was dried, the fine particles of dried poison have a pungent action on the nostrils; the taste is slightly bitter and causes an increase of saliva having a feel of frothy soapiness. I have never found any ill effects from tasting it or from the action on the nostrils; but if any gets into the eye it causes a paiuful inflammation which however soon passes off. The properties of this substance will be given more fully in Part III, Chapter IV. Before concluding this part of my subject, I may give an account of the structure of the poison fang, prefacing it with the description given by the first odontographer of the age, Professor Owen.* “ A true idea of the structure of a poison fang will be formed by supposing the crown of a simple tooth, as that of a boa, to be pressed flat and its edges to be then bent towards each other and soldered together so as to form a hollow cylinder, or rather cone, open at both ends. ***** The duct which conveys the poison, though it runs through the * Anatomy of Vertebrates, Vol. I, p. 397. 17 centre of a great part of the tooth, is really on the outside of the tooth, the canal in which it is lodged and protected being formed by a longitudinal inflection of the dentinal parietes of the pulp-cavity. This inflection commences a little beyond the base of the tooth, where its nature is readily appreciated, as the poison duct there rests in a slight groove or longitudinal indentation on the convex side of the fang; as it proceeds it sinks deeper into the substance of the tooth, and the sides of the groove meet and seem to coalesce so that the trace of the inflected fold ceases, in some species, to be perceptible to the naked eye; and the fang appears, as it is commonly described, to be perforated by the duct of the poison-gland. In the Hydrophis the groove remains permanently open. From the position of the poison-canal it follows that the transverse section of the tooth varies in form at different parts of the tooth : at the base it is oblong, with a large pulp-cavity of a correspond- ing form, with an entering notch at the anterior surface ; further on, the transverse section presents the form of a horse-shoe, and the pulp-cavity that of a crescent, the horns of which extend into the sides of the deep cavity of the poison-fang: a little beyond this part the section of the tooth itself is crescentic, with the horns obtuse and in con- tact, so as to circumscribe the poison-canal; and along the whole of the middle four-sixths of the tooth the sec- tion * * * shows the dentine of the fang inclosing the poison-canal, and having its own centre or pulp-canal in the form of a crescentic fissure situated close to the concave border of the inflected surface of the tooth. The pulp- cavity disappears, and the poison-canal again resumes the form of a groove near the apex of the fang and terminates on the anterior surface in an elongated fissure.” On one point this description is somewhat imperfect and, I may venture to venture to say, unsatisfactory; it speaks of " a canal in which it (the poison duct] is lodged and protected” and 3 18. further on, Professor Owen says “the inflected surface of the tooth can be exposed to no other pressure than that of the turgescent duct with which it is in contact.” Now, accord- ing to my observation, the poison duct ends at the bottom of the mucous envelope of the tooth and between its orifice and the basal orifice of the tooth there is no continuity ; the two orifices are in apposition and, at the moment of a bite, the saliva, having no other exit, passes through the fang-canal. A continuous canal could not exist when we consider that it would be broken at the first shedding of the fang and there is no ground for supposing any peculiar reparative powers inherent in this duct. No explanation on this point is given in Professor Owen's account of the development of the fang. “In the posterior part of the large mucous sheath of the poison-fang, the successors of this tooth are always to be found in different stages of development; the pulp is at first a simple papilla and when it has sunk into the gum, , the succeeding portion presents a depression along its inferior surface, as it lies horizontally, with the apex directed backward ; the capsule adheres to this inflected surface of the pulp and the base of the groove of the loose growing poison-fang is brought into the same relation with theduct of the poison-gland as the displaced fang which has been severed from the duct.” This description of the of the fang is perfectly correct. growth I may add that the inflected part of the capsule lining the cavity of the poison-fang appears to play a great part in its nutrition ; while the pulp-cavity becomes obsolete (or nearly so) from the apex backwards as fast as the fang grows, the capsule remains vascular until the fang is nearly perfect. The more highly developed the fang, the greater this nutritive function of the capsule appears to be. Thus, in the cobra, the pulp-cavity is visible for more than half-way 19 down the full-grown fang, whilst in the Daboia this cavity disappears very quickly, and is only marked by the darker appearance of the centre of the tooth. In fact the remains of the obliterated cavity are just traceable along the posterior wall of the canal and only appear plainly below the termina- tion of the latter. I The structure of the poison-fang can be studied in the imperfect fangs often met with in the cobra ; it frequently happens that the fang is found divested of a part of the outer wall of the pulp-cavity, so that the wall of the poison-canal is seen nearly isolated from the outer part of the fang except at the base. CHAPTER IV.-INTERNAL ORGANS. The cavity, thoracic and abdominal in one, of snakes may be divided into four parts, of nearly equal length. The first part contains the windpipe, gullet, heart and lungs, the second contains the liver, the third contains the stomach with the pancreas, spleen, gall-bladder and small intestine, the fourth contains the large intestine and the urino- genital organs. See Plate V. In front of the windpipe lies the sheath of the tongue; to the lower extremity of the sheath is attached the point of the long V shaped hyoid bone; the upper parts of this slender bone being acted on by the geniohyoid muscle and the sheath itself by the genioglossal muscle, the tongue is jerked up and protruded. The windpipe has numerous incomplete cartilaginous rings in its structure. The lungs consist of a lacework of air-cells lining the walls of large air cavities spread out along the back of the abdominal cavity from the heart to the liver. Their shape and extent vary considerably; they are most extensive in the sea-snakes, a kind naturally 20 requiring a large supply of air to be able to stay long under water. In most snakes there is but one lung, the other being atrophied. They breathe at considerable intervals; and many kinds can remain under water for nearly half an hour at a time. During the intervals between each inspiration, respiratory movements of the ribs will be observed ; the lungs acting as reservoirs of air, these move- ments are for the purpose of changing the air in the cells of the lung-tissue. The air breathed by the nostrils passes through the trachea or windpipe, the upper part of which lies on the floor of the mouth and is closed by two cartilages. The vertical slit between them forming the glottis is just opposite the inner orifice of the nostrils when the mouth is shut; it is the rapid expulsion of air through the glottis which produces the hiss of some snakes when they are angry (the noise, is something between a hiss and the spit of an angry cat). The heart is situated at about one-sixth of the distance down the body. It is composed of one ventricle incom- pletely divided, and of two auricles (atria). The division of the ventricle is sufficient to enable the pulmonary and the systemic circulation to be carried on in very much the same way as in the higher classes of vertebrata. The stomach appears to be merely the distended part of the gullet; there is little difference perceptible between them. The combined organ is well lubricated by the secretions of the jaws and its own proper secretions and is capable of great distension. Digestion appears to go on principally at the lower end, where that part of the animal which was swallowed first passes into a state of solution and the rest gradually comes down as the space becomes vacant. The intestinal canal, very little convoluted, occupies the hinder half of the abdomen; the mesentery is plentifully loaded with fat, which becomes a reserve of nutriment for 21 the long fasts which snakes often undergo. The liver lies alongside of the gullet and stomach ; it is a long organ, in two longitudinal lobes, of the usual hepatic colour and texture; it reaches upwards nearly as high as the heart, and terminates below opposite the middle of the stomach. The gall-bladder, with the other digestive glauds, is situated a little further down, at the lower end of the stomach. The end of the bowel opens into a short cloaca, the common passage of the intestinal canal of the ureter and of the ovarian or spermatic ducts, according to sex. a Just behind the end of the intestine is a little prominence in the mucous membrane of the cloaca. Below this are the urethral, above it the ovarian or spermatic orifices. The testes are two elongate white vesicular organs, not unlike full-grown silkworms in appearance. The spermatic ducts, of tortuous structure, descend close along side of the kidneys and thence accompany the ureters. The kidneys are elongate multilobular organs situated nearer to the vent. . These four genito-urinary glands alternate, the right testis and kidney being each higher than the same organ of the left side. In the female the ovaries when unimpregnated are found in the position corresponding to that of the testes; each consists of a series of colourless vesicles lying behind the intestines. When eggs are mature the ovary extends often more than half-way up the body quite effacing the intestine. The number of eggs found may vary from 5 or 6 to 30 and upwards. When the number is small I have generally found one ovary unoccupied. The male snake has a double organ of copulation lodged in the tail (which is generally longest in males) ; when protruded by pressure from behind forwards it is seen in the form of two highly vascular protuberances armed with 22 spines, emerging each from a depression at the side of and behind the anus. No canal passes passes through these, the spermatic ducts terminating some distance within the cloaca. Nearly all these organs are liable to be infested with entozoa. The mouth, lungs, and digestive canal bear little red round worms of several kinds; but Tropidonotus quin- cunciatus is remarkable for having its cellular tissue and abdominal cavity inhabited by numbers of small tape-worms about 6 inches in length. I believe that they are developed from cysts in frogs and fishes. Both kinds of entozoa per- meate the muscular tissues; I have found them emerging from under the skin of the tail, both in the abovementioned snake and in a tree-snake.* Perhaps this Chapter will be the most fitting place for a short notice of the monstrosities met with in this order of vertebrates. By far the commonest monstrosity is the possession of a double head, each head being perfectly formed and the two placed side by side. These double- headed snakes are by no means uncommon; they have been met with in America, Australia and Europe, they do not however, appear to survive their birth long, the specimens to be found in museums being of small size. There is a young two-headed Tropidonotus quincunciatus in the Madras Museum, its origin is unknown, as I found it amongst a large number of snakes accumulated in the store- rooms of the Museum. This monstrosity is, apparently, rather common amongst the sea-snakes. It is possible that a double-headed snake originated the fable of Apanden the thousand-headed naga, and his humbler representative the Sesha, or seven-headed naga so often represented in Hindoo religious art. * Snakes are externally troubled with the dog-tick. This parasite gets between the scales and fastens on to the skin. PLATE V. Windpipe Genio-hyoid Hyoid bone Genro-glossus Intermandibua marscle Gallet Lying Testis. Vena caval Iriver Spermatic duct Kidney Stomach 1. 2 Gall bladder Intestine .. Pancreas Orary Kidney Fig. 1. Internal organs of Tropidonotus quincunciatus, female. Fig. 2. Lower abdominal organs of a tree-snake, male ; the intestinal fat is drawn aside. N OF MU с 23 CHAPTER V.- THE SENSES. Sight appears to be the only sense which is well developed in snakes, at least according to the conventional standard. The scaly tegument can hardly be endowed with much sensibility: from their habit of swallowing food whole, it is probable that their taste cannot be very delicate; the nasal cavities are but little provided with expansions of mucous membrane; and hearing cannot be an important sense con- sidering the rudimentary state of the external ear. The only remaining portion of this organ is a subcutaneous capsule attached to the tympanic bone; from this a long slender bone, the stapes, * conducts any vibrations of air that may have penetrated the scales and muscles of the head to the expansion of the auditory nerve. There is no external orifice or tympanum. The eye is well developed in those snakes which live above ground, although it varies in size and adaptation according to the mode of life which it is destined to serve. It is covered by a transparent layer of epidermis, which is cast along with that of the general integument. It is unprovided with eyelids, and is moved to a slight extent by the usual muscles. The pupil varies in shape and size ; in most snakes it is round, but it is elliptical and erect in the Lycodontidæ, the Pythonidæ, the Viperina and some of the tree-snakes; and in one family of the latter it is elliptical and horizontal.† * The stapes is not readily found as it is a mere filament of elastic bone projecting backwards towards the tympano-mandibular joint, lying deep below the tympanic muscles. See Plate IV, fig. 6. + Of the three families of colubrine tree-snakes the Dendrophida have a round pupil, the Dryiophida a horizontally elliptical pupil, the Dipsadidæ an erect pupil. It is doubtful whether an elliptical pupil is a sign of specially nocturnal habits. I may mention that Mr. Gerard Krefft considers it is; he calls the Australian Dendrophidæ 'the day tree-snakes and the Dipsadida “the night tree-snakes. All snakes are more or less nocturnal animals. و 24 The iris is often tinged with various colours, yellow and green being frequent; in Lycodon, it is so black that the shape of the pupil is most difficult to see. In the Typhlopido, the eye is hardly visible at all, being very minute and covered by the lateral head-shields. The tongue is probably a tactile organ; and in some snakes there is a prolongation of the snout apparently acting as an organ of feeling (Passerita, Herpeton). CHAPTER VI.-THE INTEGUMENTS. The skin of snakes is a smooth soft tissue, generally white, sometimes coloured, giving off numerous scales (squamo) which are generally contiguous and often in- bricate or overlapping one another to some extent. In snakes which can expand the neck this skin is seen dotted over with separate scales at some distance from one another. In most viperine snakes the scales are dull, stiff and suffi- ciently imbricate to make a rustling noise if the skin is crumpled; in the burrowing snakes, a cuirass of smooth polished scales leaves hardly any interval visible; in the sea-snakes, the scales become tuberculated. In most snakes the skin is shown between the interstices of the scales during the respiratory movements. On the lower parts of the body the scales become broad (in the higher types), expanding into ventral shields (scutce) and, beyond the anus, into subcaudal shields (scutella). On the head a few snakes, Erycidæ, Acrochordidæ, Viperidoe and others, have scales like on the rest of the upper parts, but the majority have the head covered with plates (non-imbricate shields) varying but little from a normal pattern, and, when varying, doing so with sufficient regularity to form characteristic distinctions. The squamous covering of these three regions, the upper parts, the lower parts and the head, afford together such a large proportion of the characters used in classification that they require attentive study. We have already seen that each pair of ribs supports and moves a ventral shield; to each also appertains a corres- ponding transverse row of scales. The ribs not being fixed at a right angle to the vertebral column, but raking more or less backwards, the transverse row of scales corresponding to each pair is inclined backwards in a similar manner. If this incline is at an angle of 45°, the rows of scales will be crossed by lines at an equal angle in the opposite direction; the scales will be of a rhombic or lozenge shape, and the rows capable of being counted in two cross directions at about equal angles of inclination. But if the ribs be inclined at a slight angle to the spine, then the scales will be more nearly square; whilst an excessive incline causes them to be rhomboidal or elliptic, and the rows to be more or less longitudinally inclined. In the neck of the cobra, for instance, the ribs lie down like the ribs of an umbrella, the scales are consequently arranged in such acutely inclined rows as to become quite linear and imbricate ; when the snake raises the ribs, expanding the skin of the neck into what custom calls the hood, the scales are seen dotted like long grains of linseed on the stretched surface. The number of scales in each transverse series is variable but very regular. The extreme range is from 12 to 100 or thereabouts, but 13 to 25 is the range in the great majority of snakes. A number above 31 is only found in the Erycidoe, Pythonidce, Acrochordido some of the Homalopsidoe and Hydrophido. In conjunction with other characters, the number of scales in each transverse series, or, as it is com- 4 26 monly called, the number of rows (longitudinal)* of scales is a valuable distinctive character, as it is comparatively rare that individuals of the same species should have a different number of rows. In Part II it will be seen that the number of rows of scales is generally the first element in the diagnosis of species. When the physiognomy of a snake does not indicate its family the collector begins at once to count the number of scales in a transverse series along the course of a pair of ribs; but in the tree-snakes and some others it will be found more convenient to count across the ribs. This number is nearly always odd, the vertebral row being azygos, and often of a different shape; in only two genera (Zaocys and Peltopelor) is there a double row of vertebral scales, and, consequently, an even number in the transverse series. An even number of scales consequent on the doubling of the vertebral may be present as an anomaly in individual snakes. I have a Dipsas gokool with 22 rows of scales instead of 21. The number of rows should be counted at a distance from the head equal to about one quarter of the length of the body, as the number on the neck exceeds the normal number by two or more; the number settles down at a point varying from the tenth to the thirtieth ventral shield and remains constant for at least half-way down the body; then, sooner or later, the scales begin to diminish, always in uneven number, down to the root of the tail. There several rows may be observed with- out corresponding ventrals, three or four being rudimentary or deficient where the anal orifice is covered by its large shield. The number of scales on the tail is nearly always even, beginning with about ten and diminishing by pairs to four or two. * The number of transverse series is not counted ; the number of ventral shields is, practically, more constant and is stated instead, at least in the snakes with ventral shields. 27 In some snakes the number of rows of scales settles down very soon to the normal number which continues till very near the tail, in other snakes barely four-tenths of the trunk is occupied by the normal number. Thus, in Bungarus fasciatus and the genus Callophis, the number of rows settles down, at about the tenth ventral, to the normal number 15, and remains at that quite down to the vent ; but the more common arrangement is shown in the following diagram, dividing into tenths the body of a snake with 19 rows of scales :- Tenths. Head. 1 2 3 4 5 6 7. 8 9 10 Tail. No. of rows. 21 19 19 19 19 19 17 17 17 15 10 8 6 4 We have seen that the scales may be more or less over- lapping or imbricate ; another important character is the presence or absence of a raised keel along the centre of each scale. This keel is very capricious in its presence or absence, and does not correspond to the habits of the snake. It is found in ground-snakes, in water-snakes, and in tree- snakes, indifferently, and in each of these groups, the snakes with smooth scales appear to progress just as well as those with keels. The viperine snakes lave generally strongly keeled scales. These keels are generally most marked on the dorsal rows, they become faint towards the abdomen, and rarely appear on the outer row of scales. This row is generally of larger size than the others. In the Erycidoe, the keels on the caudal rows of scales are so strongly marked as to form sharp longitudinal ridges; and as they rake backwards like the teeth of a ratchet-wheel, they would apparently be of great use as aids to progression in burrowing a The presence of an opposite feature-grooves-is fre- quently noted ; they are far from obvious, and are best seen by letting the light glance off the scales; they are then visible as one or two minute gougings at the apex, , 28 The ventral shields are narrow at their first appearabice between the chin shields; the first one or two are often bifid, and as many as ten to twenty rows of ordinary scales often intervene before they begin. (All the scales which intervene between the last pair of geneial shields, and the first undivided ventral are called gular scales). The ventrals are absent, rudimentary or narrow in the burrowing snakes, the grovelling snakes, the pythons and the sea-snakes, whilst they are most developed in tree-snakes and others of active habits. In these latter they become broad, turned up at the sides, and often have on each side a lateral keel $0 well developed as nearly to divide them into three sections. The last of the ventral series is the anal shield; it is generally bifid, and this character, when it occurs, , very regular. Still more regular is the single or double condition of the subcaudal shields, scutelloe; they are gene- rally double, being divided down the centre by a zigzag line. is To this rule the following are exceptions :- Families. Genera. Calamarido.... s Aspidura Haplocercus. Lycodontido......... Cercaspis. Amblycephalidoe ...... Amblycephalus. Erycido ........ s Eryx, ? Gongylophis. Bang 00008, Elapidoe Megoerophis, Ophiophagus, Viperida Echis. In Ophiophagus, and occasionally in Naga, the last few ventrals may be double, though the anal is always single. The number of ventrals and subcaudals corresponds close- ly with that of the vertebræ. The number is variable, not @.00 } anteriorly only. 6.64 ... 29 only in different species, but in individuals of the same species; yet it is a valuable diagnostic mark. Iu some species the number of ventrals does not vary more than five per cent., in others it is very variable. Thus Tropidonotus quincunciatus has very constantly either 137 or 145 ventrals, whilst T. stolatus has from 121 to 161. The genus Ablabes is most irregular in this respect, the species having from 122 to 245 ventrals. And the genus Tragops, a well-defined genus of tree-snakes, consists of three species having respectively about 151, 190 and 220 ventrals. The number of subcaudals is very variable, it is generally greater in males than in females owing to the increased length of the tail in the former sex, The tail ends in a single shield. In most snakes this shield is not remarkably developed, but in the Uropeltidæ it becomes a broad disk either naked or covered with keeled scales, and in Plectrurus it ends in a forfical bispinous shield. In some snakes with rather short tails, it may be found quite pointed, sufficiently so to prick the skin slightly if roughly handled. The Crotalido have this point well developed, though the tail is not provided with the rattling appendages peculiar to some American genera of the family. It is remarkable however that the Indian Crotalidoe have a habit of vibrating the tail when excited, and if it strikes against any hard substance a slight noise is produced. In the sea-snakes the tail is compressed laterally forming a vertical fin like that of an eel. The extremity of the tail is liable to accidental mutilation, and it frequently happens, in consequence, that the number of subcaudals is found much below the regular number.* * The Indians have a fable that the cobra loses an inch of its tail each time that it bites a man. Stumpiness of tail is not however confined to this snake and amongst the less agile species a large 30 The head is covered either with scales like on the rest of the body, or with large plates of regular form, or with various gradations between these two classes of covering, In the greater number of vipers, there is no trace of the regular-shielded crown possessed by the majority of snakes, the head being scaly like the rest of the body ; the Erycido and Acrochordidæ have also scaly heads; the burrowing snakes have an incomplete shielded covering. In two snakes of very opposite habits, the head-covering is composed of large scales simulating the arrangement of shields; Xeno- peltis unicolor, a burrowing snake, and Peltopelor macro- lepis, a tree-viper, both solitary species of their genus, have large triangular scales occupying with considerable regularity the place of the head-shields; in the latter snake they may indeed be said to be shields simulating scales. The lowest family of snakes, the Typhlopido, is distinguished by a type of head-shielding quite different from that found in other families; the blind' snakes have become degraded by an entirely subterranean life. The normal arrangement of head-shields, about to be described, is sketched out in the skinks, a family of lizards of Ophidian appearance, from which the snake-class has evidently developed. The head-shields appear to have formed round a central shield, the vertical, which is of a shape departing but little from that of a pentagonal heraldic shield, base in front, apex behind. It sometimes becomes bell-shaped by the rounding of the posterior angles or hexagonal by the addition of a salient angle in the base-line. Behind this are the two occipitals, large, elongated, and either rounded proportion are found to be deficient in this member. I have seen several cobras with as little as two inches left of tails which should have been nine inches in length. It is probable that this mutilation is caused by a mungoos biting off the tail of a snake which has fled into a hole not quite large enough to shelter his whole length. 31 or truncated behind. In front of the vertical are two pairs of shields, the posterior frontals more or less square, and the anterior frontals of similar form, but smaller and liable to encroachment in front and at the sides. On either side of the vertical are the two supraciliaries, of regular and crescentic shape, shading the eyes. They complete the oval of the crown, covering the space between the postfrontal and prefrontal bones. These four pairs of shields with their centre, the vertical, form the crown; the other shields are on the sides of the face. The muzzle is covered by a convex triangular shield, the rostral, which often extends up a little way between the anterior frontals; it is broad at its base with a slight chink in the middle for the exit of the tongue without the mouth being opened. Behind the rostral on either side are two series of shields, one above the other; the lower series is that of the labials, (upper) varying ordinarily from five to nine in number, and increasing in size from before hindward. One or more of them enter the orbit when there is no subocular. In the Pythonidæ, the labials and rostral are indented with deep pits in the shape of a comma. The shields between the labials and the crown on either side are the nasals, the loreal, the oculars, and the tem- porals. The nasal is sometimes single, being pierced by the nostril, but more frequently there are two nasals with the nostril between them. In the water-snakes Homalopsidæ . and Hydrophida, where the nostrils are superior, the nasals of either side are often contiguous, excluding the anterior frontals from contact with the rostral. The loreal (frenale) is absent in the venomous snakes ; and in some harmless snakes, tho Calamaridæ, Tetragono- soma, Xenopeltis and several genera of tree-snakes it is 32 either absent or merged into the neighbouring shields. But in the harmless snakes it is present, as a rule, and in some it is double or triple (Ptyas, Zaocys.) Sometimes it wedges itself between the preoculars into the orbit; and conversely a preocular sometimes wedges it out from contact with the labials. This irregularity is frequently found in Tropidonotus plumbicolor. The preoculars (or preorbitals) are variable in number; one or two is the usual number; the upper is generally the larger and often reaches on to the crown, and more rarely as far as the vertical; the lower is smaller and often seems to be a fragment of a lower labial. The postoculars number usually from one to three, and extend lower down than the preoculars. The lower border of the orbit is sometimes occupied by a subocular, but this completion of the orbital ring is rare (Zamenis, certain Homalopside and Amblycephalidae) ;* the rule is for one or more labials to enter the orbit. Behind the postoculars are the temporals, variable in number, shape, and arrangement. They are counted back- wards in vertical rows; thus “2 + 2 + 3 temporals” means that behind the postoculars are two shields, one over the other, then two more, similarly placed, and lastly a set of three. They sometimes have to be counted thus î + }; this verges on total irregularity. These temporals are often irregular as they are transi- tional to ordinary scales. In one snake (Ophiophagus) the temporals join in a complete ring round the occipitals by the addition of two large shields behind them. This some- times occurs in the cobra, a snake to which Ophiophagus is closely related. * I have observed this once in a cobra ; it was an aberrant specimen in other respects. See note to Naga, Part III. PLATE VI. 1. Tropidonotus quincunciatus. o v DUT 0 yor (pel Z 17 n.n. Nasals. 1. Loreal. 0.0. Occipitals. V. Vertical. 8.8. Supraciliaries. p.f. Posterior frontals. a.f. Anterior frontals. r. Rostral. d.o. Preocular. p.o.o. Postoculars, 3. 1 to 9. Labials 9, the 4th & 5th entering the orbit. t. Temporals 2+2, in this specimen they are 2+1 (oo means irregular.) 1 to 9. Lower Labials. m. Mental. 7 6 5 )4 54 sen g.g.g.g. Gular shields. gen. Geneial scales. ges g g 9 g 6 5) V. First ventral shield. 2. Ptyas mucosus. 100 ORG 1:47 SO The loreal (1.1.1.) is triple and there are 2 preoculars (p.o.) UND TYPES OF THE HEAD-SHIELDING IN COLUBRINE SNAKES. 33 The shields covering the lower jaw are also regularly arranged. In front, corresponding to the rostral above, is a single shield, the mental and from it the lower labials go backwards, edging the lip on either side. The pair of first labials nearly always meet in the median line behind the mental, but the other lower labials, are separated by two pairs of longitudinally disposed geneial shields one behind the other. The geneials of either side are separated by a tolerably deep mental groove in all but the lower types. One or more pairs of scales (gular scales) usually intervene between the geneials and the first ventral shield. The shields above described are found in most of the higher types of snakes. Their place is sometimes filled by scales especially in the lower types, but a redundancy of shields is rarer; the multiple shields may be increased or diminished in number, but the intercalation of abnormal shields is not often met with. Zamenis diadema and the Pythonido offer almost the only examples of redundant shields on the crown. Sub-division of shields often occurs, but very rarely is the character constant; it is usually an in- dividual aberrance to be commonly found in certain species. The colour of the integument is generally resident in the scales, although it frequently happens either that the true skin partakes of the colour of the scales or that the scales show between their edges the ground colour of the skin beneath. This skin is usually white, but black cross-bands on it are not uncommon, as also reticulated patterns in yellow, red, or pale blue. The two latter colours come and go in the same manner as the colours of a turkey's wattles, and they are often interchangeable in the same individual, e. g. Tropidonotus stolatus. The scaly coat has generally a ground-colour of olive brown in various shades and tints. Other colours also commonly occur, black, brown, yellow, green, white and more rarely red and blue. Green 5 34 a is the usual colour of tree-spakes; it is very delicate, and rapidly passes through changes from tender green to bronze and blue. In a few cases the colours are dead, but generally they are shining, even iridescent in certain lights, and afford a beautiful play of colours. The patterns in which these colours are arranged are often very difficult to describe, and it is by no means easy to imagine the actual pattern and colours of a snake from a verbal or written description however accurate. The entrance of an interstitial pattern from the skin below, the secondary patterns produced by dark tinged margins to the scales, and the play of colours in different lights, sorely tax the word-painter's power of description. The patterns are formed by stripes and by series of dots, of ring-spots, of ocelli or of other shaped marks in a longitudinal or in a transverse direction, orin both. The longitudinal linės may cross the transverse lines or vire versâ, and the points of crossing may be marked by a different colour. Cross- bars are often ocellate, that is, including eyes in their course, and a fasciolated pattern is common; it consists of cross- bars of variegated colour produced by darker or lighter tips to certain series of scales. It frequently happens that cross-patterns are unsymmetrical, the bars of either side not meeting exactly at the median line. Cross-markings rarely extend all round the body, except in a few snakes encircled by rings; generally the under-parts are of a different pattern, plain, mottled, banded, or spotted. The throat is also of a different colour, lighter, often yellow. The head is sometimes marked with fillets, and streaks frequently pass downwards or obliquely backwards from the eye to the throat. Collars are very common, either > shaped (point forward) or < shaped (point backward). The exact period at which snakes cast their skins is very variable, but about two months appears to be the average . a a 35 a interval between each cast. At the approach of the casting, the colours of the snake become somewhat dull, and a white film is seen over the surface of the eye. When the skin, or rather the epidermis (for it is the colourless scarf skin which separates, like in human beings after an attack of scarlet fever) is ready to be cast, the snake rubs the skin back from his nose and chin, and seeks some projecting point such as would be afforded by a split bamboo, some stiff thatch, or a heap of stones, on which to catch the loose skin ; perhaps adhesion is aided by the application of glutinous saliva; anyhow the snake manages to stick the loose skin of the nose and chin to some convenient object, and then proceeds to peel himself out of his epidermis which of course remains inside out like an eel's skin after the involuntary exit of its tenant-with this difference, that the snake has had numerous opportunities, denied to the eel, of becoming used to the process. The cast skins are beautiful objects, there is often not a break in them from nose to tip. The epidermal covering of the eye comes off along with the rest of the skin, and every scale, every keel is distinctly marked; colour alone is absent,* but even without it the kind of snake to whom the skin belonged can often be identified.† They are very delicate and fragile, and are liable to destruction by mites unless kept shut up along with camphor. The cast skin of a Ptyas mucosus, 9 feet long, weighs 130 graius or a little over a quarter of an ounce. a * The pattern of the Python and of some Dipsadidæ is visible in their cast skins. † When I was stationed at Kamptee in 1868, the house I occupied jointly with a brother-officer, also gave shelter to a cobra and a pair of Bungarus arcuatus. I never saw them, but easily identified them by the skins they periodically cast. The cobra lived on my friend's side of the house, the other snakes lived in a hole in the wall under my dressing table, 36 PART II.--CLASSIFICATION, CHAPTER I.-PRINCIPLES. The following synopsis of the families of Indian snakes with their sub-divisions is here presented in order to give a general idea of the system of classification in use, before entering into the details of the Descriptive Catalogue : ORDER. OPHIDIA. FIRST SUB-ORDER. HARMLESS COLUBRINE SNAKES. (Serpentes colubriformes non-venenati.) A. SNAKES OF. LOW TYPE. VENTRAL SHIELDS ABSENT OR NARROW. HEAD SHIELDING DEFECTIVE OR ABNORMAL. Fam. I. TYPHLOPIDÆ. Blind Snakes. Genera. Small and quite cylindrical, resembling at Typhlina. first sight earth-worms rather than snakes. Onychocephalus. Eyes rudimentary, no ventral shields, forepart of the head covered with shields of a peculiar type. Rudimentary hind limbs, hidden. Bur- rowing snakes, rarely appearing above ground. Fam. II. TORTRICIDÆ. Short-tailed Earth snakes, Body cylindrical; tail very short, conical. Cylindrophis. Eye small. Head shielded, but only one pair offrontals; ventralshields beginning to appear. Palatine teeth; Median groove at the chin. Rudimentary hind limbs visible. Burrowing snakes, occasionally found above ground. 37 Fam. III. PYTHONIDÆ. Pythons. Body very thick; head depressed, abnor- Python. mally shielded. Labial shields pitted. Ventrals very narrow, 240 or more. Scales smooth, 65 or more. Rudimentary hind limb visible. . Fam. IV. ERYCIDÆ. Sand Snakes. Body thick, tail very short, narrow ventrals, Gongylophis. Cursoria. numerous rows of scales. Crown of the head Eryæ. scaled. Rudimentary hind limbs generally present. Fam. V. ACROCHORDIDÆ. Wart Snakes. Head small; eye small; nostrils superior. Acrochordus. Chersydrus. Entirely covered with small tubercular or spiny scales, no ventrals or subcaudals. Tran- sitional to the sea-snakes. Fam. VI. UROPELTIDÆ. Rough-tailed Earth-Snakes. Plectrurus. Body cylindrical ; head short, conical; tail Rhinophis. very short, ending in a rough or scaly disk, Silybura. generally obliquely truncated. Head shielded, Melanophidium. but only one pair of frontals; ventral shields apparent. No palatine teeth. Burrowing snakes, living at some distance under ground. Fam. VII. XENOPELTIDÆ. Iridescent Earth Snakes. Body cylindrical; tail short, tapering; head Xenopeltis, flat, depressed, covered with large triangular shield-like scales. Burrowing snakes transi- tional to the more highly developed families. 38 B. SNAKES OF INTERMEDIATE TYPE. VENTRAL SHIELDS FAIRLY DEVELOPED. HEAD-SHIELDING DEFECTIVE OR ABNORMAL. Fam. VIII. CALAMARIDÆ. Grovelling Snakes. . . Body cylindrical; head small; tail tail short, Calamaria. Macrocalamus. tapering. Eye small; ventral and subcaudal Oxycalamus. Geophis. shields well developed ; head shielded, but with Aspidura. ; Haplocercus & 3 one or more shields absent (generally one or or 1 new genera. more anterior frontals, and the loreal). Small snakes, living on the surface, under trees, stones, &c. Fam. IX. HOMALOPSIDÆ. HOMALOPSIDÆ. River Snakes. Body cylindrical; tail moderate, compressed Fordonia. Cantoria. at the root. Ventrals rather narrow. Nostrils Cerberus. Hypsirhina. superior, provided with a fleshy valvule. Perania, Homalopsis. Head-shields often irregular, anterior frontals Hipistes. encroached on by the large nasals. The last Herpeton. tooth is transitional between a tooth and a poison-fang. Rarely found far from the water. Fam. X. AMBLYCEPHALIDÆ. Blunt-headed Snakes. Body compressed, slender; head short and Amblycephalus, thick. Often a complete orbital ring of shields. Cleft of the mouth small, lower jaw not expan- sible, no mental groove. Gerarda, Pareas, C. SNALES OF HIGH TYPE. VENTRAL SHIELDS FULLY DEVELOPED. HEAD-SHIELDING NORMAL.* Fam. XI. OLIGODONTIDÆ. Filleted Ground Snakes. Head normally shielded, with peculiar mark- Oligodor ings. Teeth few in number, in one genus no palatines. Simotes. * With a few exceptions in the genera Ablabes, Atretium and Zamenis, of the family Colubridæ, the crown and orbital shields are always normal in the families of this section. 39 Fam. XII. LYCODONTIDÆ. Harmless-fanged Snakes. Head depressed; snout spatulate and flat. Lycodon. Tetragonosoma. Eye small, generally with vertical pupil. A Leptorhytaon. Ophites. large fang in front of the maxillary and mandi- Cercaspis. ble, but not grooved or hollow. Fam. XIII. COLUBRIDÆ. This family comprises all those harmless snakes which do not present any striking cha- racter, are fair and moderate in their propor- tions, and have none of the qualities necessary for their admission into other families. Their head-shields are normal, with the exception of a few species on the debatable ground betwixt this family and the Calamaridæ; they have not the compressed and slender body of the tree-snakes, yet some of them climb and have a green coloration; they have not the superior nostrils and aquatic build of the true fresh-water snakes, yet some of them are am- phibious. They are divided into the following groups: Group I.--CORONELLINA. Ground Colubers. Of small size, with smooth scales; in some Ablabes. Cyclophis. genera aberrant species approach the Calama- Odontomus. Nymphophidium. ridæ in imperfect head-shielding. Elachistodon. Coronella. Group II. ---COLUBRINA. Agile Colubers. Attain a large size. Their scales are keeled, Coluber. Elaphis. they are active enough to climb and swim on Compsosoma. Cynophis, occasions, and are swift in their movements Ptyas. Xenelaphis. along the ground. Zamenis. 40 Group III.-DRYADINA. Bush Colubers. Their compressed body, numerous ventrals Zaocys. Herpetoreas. (200 or more), and general green coloration show that they are transitional to the families of true tree-snakes. Atretium. Group IV.-NATRICINA. Amphibious Colubers. These lead off to the river-snakes; their Tropidonotus. nostrils are often superior; their scales are Xenochrophis. Prymnomiodon. always more or less keeled; the ventrals con- Cadmus. siderably less than 200; long teeth at the back of the maxillary Fam. XIV. DENDROPHIDÆ. Tree Snakes. Body slender, snout rather long but rounded Gonyosoma. Phyllophis. fairly; eye moderate or large with round Dendrophis. Chrysopelea. pupil. Ventrals broad with two lateral keels. Thag Ops. Fam. XV. DRYIOPHIDÆ. Long-nosed Tree Snakes. Body excessively slender; head narrow with Tropidococcyx. the rostral shield developed into a snout often Passerita. of some length. Eye moderate with horizon- tal pupil. Fam. XVI. DIPSADIDÆ. Broad-headed Tree Snakes. Body slender, much compressed. Head very Dipsas. distinct from the neck, short and broad. Eye moderate, with vertical pupil. Fam. XVII. PSAMMOPHIDÆ. Desert Snakes. A class of snakes resembling the tree-snakes Psammophis. Psammodynastes. in their form, but of terrestial habits. Body slender, head very distinct from the neck, head- shields normal. 41 SECOND SUB-ORDER.. VENOMOUS COLUBRINE SNAKES. (Serpentes colubriformes venenati.) Snakes in which the front of the maxillary is furnished with a short poison-fang always more or less erect. Fam. XVIII. ELAPIDÆ. Venomous Colubrine Land Snakes. Land-snakes. Head normally shielded, but Naga. Ophiophagus. no loreal. Baga Lus. Xenurelaps. Megcerophis. Callophis. Fam. XIX. HYDROPHIDÆ. Sea-Snakes. Tail compressed into a paddle. Head-shields Platurus. Aipysurus. tolerably regular, nasals generally contiguous. Disteira, Acalyptus. Ventrals narrow or none. Scales tubercular Hydrophis. Enhydrina. and dull. Eye small; nostrils superior. THIRD SUB-ORDER. VIPERINE SNAKES. (Serpentes viperini.) Snakes with a long poison-fang, capable of complete depression. Fam. XX. CROTALIDÆ. Crotali or Pit-Vipers. Broad thick head, very distinct from the Trimesurus, Peltopelor. neck, and generally scaly or imperfectly Calloselasma. Halys. shielded. A deep pit between the eye and the nostrils, corresponding to the antrum maxillce. Pelamis, and the Hypnale. Fan. XXI. VIPERIDÆ. Vipers. Daboia. Echis. Broad thick head, scaly. No facial pit. The order in which I have arranged these families differs somewhat from that adopted by Günther; the improvement, if any, is very slight, for it is difficult, especially when the Indian genera are alone considered, to arrange the families 6 42 in groups which will show the affinities of the families which compose them. But the present arrangement is less dis- onant from the order of development shown by the families when compared with the primitive lacertilian type, and it renders diagnosis of an unknown snake easier than when the families are arranged in entirely empirical order. I imagine that the process by which development has taken place must have been somewhat on the system shown below, and I have no doubt that a consideration of general ophiology and not that of India alone, would fill up many hiatus at present evident. 00 43 Scheme of development from the original type represented by the family TORTRICIDÆ. Elapidæ Dendrophidae Oligodontidæ- Colubrina-Dryadina-Dendrophidæ Hydrophidæ--Homalopsidæ-Natricina-Coronellina --Psammophidæ-Dipsadidæ - Acrochordidæ Lycodontidæ- Calamaridæ --Viperidæ-Crotalidæ -Xenopeltidæ -Uropeltidæ TORTRICIDÆ --Erycidæ ---Pythonida--Amblycephalidæ Typhlopidæ 44. CHAPTER II.-- DIAGNOSIS OF AN UNKNOWN SNAKE AND METHOD OF DESCRIPTION. The student of Ophiology should take some common and well-known snake such as Ptyas mucosus and practise making the description of it with a view to familiarize him- self with the various characters. He should also practise drawing the head-shields; to do this correctly, he must begin by drawing the vertical, and then gradually build up the other shields round it; to draw a snake full length in a natural attitude is a difficult task to any but a cunning limner ; but an exact representation of the head and neck is possible to any one who will take a little trouble about it. Colouring the drawing accurately is far from an easy task, and requires some study of the natural process by which the colours have become blended. When an unknown snake is required to be identified, the first step is to determine the family to which it belongs. This can be done readily by means of the synopsis given in the preceding Chapter. If the snake be found to belong to the harmless Sub-order its place in the three Sections into which I have divided the families should be first determined after which the diagnosis of family, genus and species can be completed by reference to the Descriptive Catalogue further on. If it does not appear to belong to any of the species described, an accurate description should be drawn up, while the specimen is fresh, for future reference in case it should turn out to have been hitherto undescribed It is necessary to lay down a system of description for snakes in general which will prevent useless details being given and direct the attention to the important points. Accurate description may be given very neatly in Latin ; we must try and imitate in English the conciseness of the more 45 classical description. The following scheme will give an idea of the way in which the description should be arranged. Date Place Length ; tail Sex Scales-_-rows; smooth, keeled, or with apical grooves; imbricate ? rounded, oval, linear, rhombic or rhomboidal; vertebrals enlarged ? at what distance in tenths of length the number diminishes. Ventrals, number; broad or narrow (in proportion to the circumference); keeled ? turned up at the sides ? Anal, single or bifid. Subcaudals, number; single or double. Head, distinct from neck ? high, flat, broad, narrow; snout acute, obtuse; eye large, small, moderate; pupil round, erect, horizontal; iris, colour. Head shields, normal ? note peculiarities of crown shields; loreal present, absent, single or multiple; nasal single or multiple, position of nostril. Preoculars, number, does the upper one reach to the crown-to the vertical ? (Subocular), Labials, number, how many enter the orbit, peculiarities; temporals, number, arrangement. Lower jaw-labials, number, first pair not contiguous ? geneials, number of pairs; gular scales, number. Ground colour. Longitudinal pattern. Stripes or streaks, number, breadth, position (vertebral, dorsal, lateral). Series of spots, of ring- spots, size, margins, disposition. Transverse pattern. Cross-bars or cross-bands, sagittal, fasciolated, quincuncial, decussating, ocellated, margined ; series of rings (number). Interstitial colouring. 46 Belly and ventral row of scales, throat, subcaudals- ground colour, plain, marbled, marbling, striped, spotted, &c. Head, ground colour; cross-bands, fillets, > or