L I B RAHY OF THE U N IVER.SITY OF ILLINOIS 570-5 ILL v. 24 CO p 2 which it was withdrawn on or before the Latest Date stamped below. L161— O-1096 Digitized by the Internet Archive in 2011 with funding from University of Illinois Urbana-Champaign http://www.archive.org/details/myologyofwhoopin24fish Illinois Biological Monographs VOLUME XXIV University of Illinois Press URBANA BOARD OF EDITORS Leland Shanor Harvey I. Fisher H. Orin Halvorson William R. Horsfall Aubrey B. Taylor CONTENTS No. 1 The Mammals of the Huachuca Mountains, Southeastern Arizona DONALD F. HOFFMEISTER AND WOODROW W. GOODPASTER No. 2 The Myology of the Whooping Crane, Grits americana HARVEY I. FISHER AND DONALD C. GOODMAN Nos. 3-4 The Genus Lysimachia in the New World JAMES DAVIS RAY, JR. ILL. ,.24* The Myology of the Whooping Crane, Grus americana HARVEY I. FISHER and DONALD C. 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GOODMAN Illinois biological monographs: Volume xxiv, No. 2 THE UNIVERSITY OF ILLINOIS PRESS URBANA, 1955 Board of Editors: leland shanor, harvey i. fisher, h. orin halvorson, WILLIAM R. HORSFALL, AND AUDREY D. TAYLOR. Distributed: December SO, 1955 Copyright 1955, university of Illinois, lidrary of congress catalog card no. 55-6941. 5 10.5 Preface The Whooping Crane, Grus amcricona (Linnaeus), has long been an interesting species of the American avifauna. Its size and color, its stately bearing, and its "whooping" call have made it noteworthy. In recent years its rarity and the consequent publicity have caused increased attention from ornithologists and the general populace. Robert P. Allen ( 1952 ) has gathered all the information available for the species and has emphasized the dwindling population. In 1940 only 33 individuals were known. It is possible to be fairly accurate about the numbers because all the birds now winter in a limited area in Texas which has been set aside as the Aransas National Wildlife Refuge, and because these large, white birds are there obvious to any observer. From 1940 there was seemingly a gain of about one bird every three years until 1949, when the total population numbered 37, including two captives. The spe- cies has decreased since. With such a low rate of net increase as has been observed and with most losses occurring on migration where protection is difficult, it is perhaps not too pessimistic to regard the Whooping Crane as a nearly extinct species. Its fate may depend in part upon an educa- tional program extending from the Slave Lake region of Canada to the Gulf Coast of the United States. This program might reduce losses such as occurred when two birds died during the fall migration of 1952; one of these had been shot. The loss of these two birds within one month nullified the probable increase of the preceding six years, if we can indeed expect but one individual to be added to the population in every three- year period. This rarity was one of the reasons the senior author initiated an anato- mical study in 1948. Only scattered notes about the morphology of the Whooping Crane can be found in the literature, and most of these are incidental to work on other species. The monographs by Blaauw (1897) and Blyth ( 1881 ) on the cranes only mention structure and give nothing of importance to this study. Lowe (1931a and 1931b) published ana- tomical studies of some gruiform species but nothing in detail on Grus americana. The same may be said of Mitchell's papers of 1901 and 1915. Coues (1874), Roberts (1880), Forbes (1882) and many others have noted the invasion of the sternum by the trachea. Ridgway and Fried- mann ( 1941 ) and Beddard ( 1898 ) have summarized some of the known anatomical features of the genus. The latter publication, despite much myological information on other species of the genus, is marked by the absence of any data for the Whooping Crane. Hudson (1937) has re- ported on the muscles of the leg of Grus canadensis. Fiirbringer (1888) VI THE MYOLOGY OF THE WHOOPING CRANE included the wing musculature of Anthropoides paradisea in his mono- graph, and Gadow ( 1891 ) in his myological section referred to Grus, and sometimes specifically to G. leucogeranus and to G. canadensis. A few other minor references to specific information on the genus and species will be discussed where pertinent. Thus it is evident that published in- formation on the structure of G. americana, particularly the myology, is virtually nil. With this in mind, it was felt that the species should not disappear, as did the Passenger Pigeon and others, without more com- plete knowledge of its structure. Purely from the standpoint of the anatomist working with birds, it was desirable to have a complete myological study. To date there is but one such study of any avian species, Shufeldt's myology of the Raven ( 1890 ) . Kaupp (1918) has discussed the myology of the chicken, but the treat- ment is very abbreviated. There are, of course, comparative and de- scriptive studies of the muscles of various regions of the avian body, but it is impossible to find in any language any other detailed study of all the muscles of one species. It is even impossible to use several papers to piece together for a species a complete work of this nature. Related to this reason for the study is the fact that the nomenclature of the muscles in birds is in a state of confusion. By careful study of the papers on the different regions, we have tried to introduce a common, stabilizing element into the confusion in naming muscles. In no sense, however, can this study be considered as of primary importance in the homologizing of muscles; our specimens were too few to permit detailed studies of the innervation in most regions. Another, perhaps the initial, stimulus for our work was the availability in 1948 of the first specimen, incomplete though it was, preserved in alcohol. Harvey I. Fisher Department of Zoology, Southern Illinois University Donald C. Goodman Department of Anatomy, School of Medicine, University of Pennsylvania Contents materials 1 acknowledgments 5 METHODS 6 MUSCLES OF THE SKULL AND JAWS 7 MUSCLES OF THE TONGUE REGION 26 MUSCLES OF THE ORRIT AND EAR 37 MUSCLES OF THE WING 39 MUSCLES OF THE TAIL 71 MUSCLES OF THE LEG 76 MUSCLES OF THE RODY WALL 103 MUSCLES OF THE VERTERRAL COLUMN 107 DISCUSSION 119 BIRLIOGRAPHY 125 List of Illustrations Superficial muscles of head and throat, lateral view 10 Muscular attachments on skull and lower jaw 11 Deeper muscles of head and anterior vertebrae, lateral .... 13 Muscular attachments on posterior end of skull 16 Deepest muscles of head and anterior vertebrae, lateral. . . 19 Deep muscles of anterior vertebrae, ventral 21 Muscles of jaw and anterior vertebrae, ventral 22 Deep muscles of posterior end of skull and jaw, ventral. . 24 Tongue and floor of pharynx, dorsal 28 Muscles of tongue and anterior part of trachea, ventral. . . 30 Muscles of posterior part of trachea and syrinx, lateral ... 34 Larynx and muscles around glottis, dorsal 36 Muscles of eyeball, medial 37 Brachial plexus of right side, dorsal, innervations of muscles 40 Brachial plexus of left side, dorsal, innervations of muscles 41 Superficial muscles of breast and wing, ventral 44 Variations in deep breast muscles, ventro-lateral 46 Superficial muscles of shoulder and wing, dorsal 50 Deep muscles of shoulder, lateral 56 Deep muscles of forewing, dorsal 60 Deep muscles of forewing, ventral 63 vii Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. Fig. 8. Fig. 9. Fig. 10. Fig. 11. Fig. 12. Fig. 13. Fig. 14. Fig. 15. Fig. 16. Fig. 17. Fig. 18. Fig. 19. Fig. 20. Fig. 21. Fig. 22. Fig. 23. Fig. 24. Fig. 25. Fig. 26. Fig. 27. Fig. 28. Fig. 29. Fig. 30. Fig. 31. Fig. 32. Fig. 33. Fig. 34. Fig. 35. Fig. 36. Fig. 37. Fig. 38. Fig. 39. Fig. 40. Muscles of trunk, dorsal 65 Muscles of tail, dorsal 71 Muscles of tail, ventral 74 Superficial muscles of vertebrae, trunk, and leg, lateral. ... 78 Superficial muscles of leg, medial 80 Sacral plexus, ventral 84 Sacral plexus, lateral, innervations of muscles 85 Second layer of muscles on breast, body wall, and leg, lateral 87 Deep muscles of thigh, lateral 89 Deeper muscles of thigh and shank, lateral 92 Deepest muscles of hip and thigh, lateral 95 Muscles of upper shank, lateral 96 Deeper muscles of upper shank, lateral 98 Third layer of muscles of upper shank, antero-lateral 100 Deepest muscles of upper shank, lateral 101 Superficial muscles of vertebral column, lateral Ill Diagram of details of M. longus colli 113 Diagram of details of Mm. ascendentes 115 Deep muscles of neck, dorsal 117 Materials Preserved specimens, other than skins, of Whooping Cranes are even fewer than the living birds. For example, the senior author, in gathering material for an osteological study of the genera Grtis, Balearica, and Anthropoides, could not locate a single complete skeleton of Grus ameri- cana and only two that were reasonably complete. Most osteological specimens consist of one or a few bony elements. There is an unverified report that the Senkenberg Museum in Frankfurt has complete skeletons of a male and a female that died in captivity, but we have not been able to check this. It is our belief that the three birds used in this study were the only ones preserved as alcoholic specimens. In the fall of 1948 the first specimen was received from the United States Fish and Wildlife Service through the courtesy of Mr. Robert P. Allen and Dr. John W. Aldrich. It had been skinned, and the head was missing, as were the entire wing and the leg distal to the knee. For ship- ment from Texas to the United States National Museum the carcass was frozen. At the museum it was preserved in 70 per cent alcohol for ship- ment to the University of Illinois. The following information concerning this specimen is taken from a letter of January 18, 1949, to Harvey I. Fisher from Robert P. Allen: It is not known when this individual received the original wound that broke the bones of the left wing. It was first noted in December, 1947, when my notes read: "Dec. 14, 1947 — Ground inventory. Note on the 'Summer Pair': evidently both of these birds have injured left wing." This was on the Aransas National Wildlife Refuge near Austwell, Texas, where most of the surviving Whoopers winter. This "pair" (They may be merely companions) had spent the summer, and it was now presumed that failure to migrate was a result of injured wings that prevented flight. A certain percentage of the Texas flock lives outside the refuge area and are subject to illegal shooting by waterfowl hunters in the nearby bays. This pair became accustomed to whole yellow corn bait as the winter ad- vanced and by this means were kept on Long Pond on the refuge and away from the shore of the Intercoastal Waterway, where they often fed on blue crabs (CaUinectes sapidus), mud shrimps (Callianassa) and other small in- vertebrates of the region, as well as killifishes, these items comprising their normal winter food. However, on March 14th I left for Louisiana to investi- gate the status of two captive Whooping Cranes we were holding there and did not return until March 20th. During this brief period the two injured Cranes presumably wandered once more to the shore of the Waterway. On March 24th this individual of the pair was found lying down on the edge of Salada Pond. Dried blood (at first thought to be dried mud) was noted on its neck and upper breast. When I tried to approach, it walked in labored manner towards Mustang Slough. The next morning, with the help of refuge personnel, the bird was captured. Left wing was hanging heavily, breath was labored, bird thin and weak. We carried it to headquarters, phoned for a vet but the bird died at 11:30 a.m. 2 THE MYOLOGY OF THE WHOOPING CRANE With Russel Clapper's assistance the bird was skinned and it was discovered that the neck had been pierced by a bullet, apparently from a .22 calibre rifle. Trachea was shattered and wound clotted. Examination also showed that the old wound had broken humerus completely, the ends being separated by weight of wing so that healing was impossible. The ulna was shattered. The following measurements were made before skinning: Weight at time of death 10 lbs. 5 ounces. Culmen 133 mm. Wing 619 mm. Tibia 329 mm. Tarsus 278 mm. Mid-toe (to "heel") 138 mm. Hind toe 30 mm. Outside toe 110 mm. Inside toe 87 mm. Palmation (relaxed) 24.5 mm. (depth) Palmation (extended) 38 mm. Spread 2209 mm. (87 inches) T. L. (contour) 1289 mm. T. L. (chord) 1257 mm. Base of tarsus (circum.) 1 & 7 /s inches. Extreme width of track 7 inches Brains weighed 314 grams. Bird lice, eyeballs and oil gland were sent to Dr. Aldrich in separate con- tainers. The skeletal remains of this specimen are now No. 347355 in the series of the United States National Museum. Dissection showed it to be a female. The sacond specimen (KU No. 31198) was found October 31, 1952, by Mr. Thane S. Robinson. The location was 8.5 miles south of Sharon, Barber Co., Kansas. Mr. Robinson telephoned Dr. E. Raymond Hall who notified Dr. Clarence Cottam of the United States Fish and Wildlife Service. Employees of this service picked up the crippled crane that same day and transported it by truck to Mineral Wells, Texas, where it died November 1. The carcass was then taken to San Antonio. On November 6 the now frozen specimen was flown by pilot Hanson to Topeka, where it was secured by Drs. Tordoff and Hall. Measurements of this female, taken before skinning, include: Weight— 13.25 lbs. Middle toe with claw— 132 mm. Chord of wingspan — 7 ft. Exposed culmen — 152 mm. Chord of wing — 612 mm. Bill from ant. end nostril — 90 mm. Arc of wing — 632 mm. Angle of gonys to tip of mandible Tarsus — 309 mm. (= length of gonys in Baldwin, etc.) — 66 mm. No physical injuries could be found when the bird was skinned by Tordoff and Fisher, or even when it was dissected. There was no evi- dence that the bird had been shot. MATERIALS .3 In late November, 1952, we received a report that a bird had been shot in Canada and transported to Texas. It subsequently died, was frozen, and shipped to us December 1, 1952. We skinned this female and sent the skin to the National Museum of Canada. The skeleton is preserved at Southern Illinois University. The history of the bird is pieced together in the following excerpts from letters to Harvey I. Fisher: From Mr. Fred Bard— March 6, 1953: To review the events that took place when we were notified of the capture of a wounded Whooping Crane at Griffin, Saskatchewan. The bird was appar- ently seen a week or two earlier by Mr. Orville Blosser, a nephew of Mr. P. E. Barlow of Griffin, a farmer, who saw and caught the Crane on October 30th. The Crane was apparently walking around in a stubble when he spotted it quite early in the morning. He pursued it with the truck, chasing it into a willow bluff in the field. He threw his coat over the bird and picked it up. The bird was placed in the back of his truck and he drove to Weyburn, where he contacted Mr. Jim Mahoney of the Weyburn Branch of the Fish and Game League. Mr. Mahoney 'phoned me reporting the capture of a bird and that it had been injured. I instructed him to call in a veterinarian and do whatever they could for the bird. When Mr. Lahrman and I lifted the bird from the crate and placed it on the straw, we noticed one leg badly twisted and on examination found the socket joint to be completely through the skin and twisted around in the wrong way. I then contacted Dr. H. L. Watson, a physician and surgeon who agreed to come out and examine the bird. That evening Dr. Watson checked the joint. I had in the meantime set it as best I could and put it in splints. The joint seemed to be properly set and Dr. Watson sutured the tendons and the skin covering the joint; antiseptics were used and the damaged leg joint placed in a cast. The bird was fed from time to time. The first feeding was a little water, and the next fresh goldeneye fish. It seemed to take these reasonably well, and in a few hours seemed to look somewhat brighter. Later attempts were made with wheat soaked in water, and some milk with aureomycin given by Dr. Watson. On Sunday afternoon the plane, dispatched from Minnesota with Ross Han- son as the pilot, left Regina with the injured bird for San Antonio Zoo. Mr. Ralph Stueck of Abernathy offered to accompany the bird on this trip to feed and water it and so relieve the pilot of these duties. From Mr. Rossalius C. Hanson — February 6, 1952: Mr. Bard, or his associates, picked up the crippled Whooper from a rancher in the vicinity of Weyburn, Sask. The bird, at that time, had a crippled left wing and broken left leg. The wing injury appeared to be a shot wound, while the leg injury was believed sustained during capture by the rancher. He had an M.D. work on the bird and they amputated the wing at the wrist and set the leg in a cast. The bird was treated with penicillin and oral aureomycin. At the time I picked up the bird it had a bad rattle in its throat, indicating a respiratory condition. This may have been due partially to the administering of the oral aureomycin with a syringe and on the other hand it may have been an outcome of the bird's lowered resistance. During the flight from Regina to San Antonio the bird was force-fed, but regurgitated most of the food during the trip. It retained some meat particles 4 THE MYOLOGY OF THE WHOOPING CRANE fed it on the second day of the trip. Soaked wheat and eggs were not retained. The bird was picked up on Nov. 2, by myself at Regina, and deposited at the San Antonio Zoo on Nov. 4. No drugs were administered during the flight. The bird was in a very weakened condition at the start and during the flight did not show any improvement. I delivered the bird to Mr. Fred Stark, Director, San Antonio Zoo, San Antonio, Texas and he administered to the bird from then on. From Dr. Clarence Cottam — December 24, 1952: Unfortunately, I do not have the exact date it died, but it was within a day or so of November 6. No measurements of significance could be made from this last speci- men which was badly emaciated and had a wing amputated at the wrist as well as a broken leg. Acknowledgments Our appreciation goes to Mr. Robert P. Allen of Tavernier, Florida, for preserving the original specimen which was the major impetus in initiating this work, and to Dr. John W. Aldrich of the United States Fish and Wildlife Service for sending the specimen to the senior author. Dr. Harrison Tordoff and Dr. E. R. Hall of the Museum of Natural History, University of Kansas, were responsible for our receiving the second speci- men. Dr. Tordoff aided the senior author in skinning the bird in such a way as to make possible the preservation of a complete skin and a com- plete skeleton. He also supplied measurements and other data. Mr. Thane S. Robinson first located this bird in the field. We wish to thank the Canadian government for granting permission for us to retain the carcass of the Saskatchewan bird. Dr. Clarence Cot- tam of the United States Fish and Wildlife Service made all the arrange- ments. Acknowledgment of aid rendered is also due Mr. Orville Blosser of Griffin, Saskatchewan, Mr. Fred G. Bard, director of the Provincial Museum of Saskatchewan, Mr. Rossalius C. Hanson of Winona, Minne- sota, and Mr. Fred W. Stark, director of the San Antonio Zoo and Aquar- ium. All these individuals took part in the capture or care of this bird. Dr. Robert W. Storer of the Museum of Zoology, University of Mich- igan, kindly sent a Little Brown Crane to us. Mr. Charles A. McLaughlin of the Zoology Department, University of Illinois, inked and labeled the final drawings, and we are grateful for his skill and patience. Finally we express our gratitude to the Research Board of the Graduate College, University of Illinois, for enabling the junior author to participate in the work in 1952 and 1953. His contribution as a research assistant was in part the result of financial support by the Board. Methods Dissection proceeded very slowly and copious notes were taken on all organ systems. We attempted to gather all possible information. How- ever, having only three specimens, it was not possible to treat all systems completely; some structures were invariably displaced and ruptured in work on other features. For example, innervations in the head region could not be studied without destroying muscles, and it was not simply a matter of taking off a layer of muscle and the attendant nerves. Life- size, or in many instances twice life-size, scale drawings were made as we dissected. One major difficulty was that all specimens had been frozen before we received them. In frozen condition the tissues are very brittle and easily broken by any strain; such breakage was sometimes extensive in the neck, axillary, and pubic regions. Often it was necessary to study all three specimens to obtain a clear picture of the muscles in a region. In general, the procedure was as follows: As the first bird was dis- sected, notes and drawings were made. Subsequent work on the other birds was compared with these notes and drawings. Any variations be- tween individuals or between sides of the same individual were recorded in notes and drawings. Finally, a rough manuscript was prepared and checked against all dissection notes and drawings. The final drawings represent composites in part, for we have tried in most instances to illus- trate the "usual" condition, but all the illustrations are made from speci- mens of Grus americana and to accurate scale. As discussed previously, the nomenclature of avian muscles is difficult. With one exception (M. dermoglossus ) , we have not introduced any new names. We have tried, by careful study and comparison, to use the most appropriate names already in literature. For names of muscles in the wing, tail, and leg we have followed Fisher (1946), who prepared comparative tables of their nomenclature. For the rest of the muscles we have included similar lists of names at the beginning of the appropriate section. The order of discussion of muscles in each section follows the sequence of listing in the table. The osteological terminology follows Howard (1929). Both authors have been active in all aspects of this anatomical study. No part can be said to be entirely the work of either one. Any part first done by one of us has been checked in detail by the other, on the same or subsequent specimens. Muscles of the Skull and Jaws The muscles are listed here in the sequence followed in the text. M. dermo-temporalis M. dermo-temporalis— Shufeldt (1890:5-6) part M. cranio-cervicalis — Edgeworth (1935:283) M. cucullaris, caput portion M. cucullaris, kopftheil— Furbringer (1888:1056), Gadow (1891:107-109) M. complexus— Gadow (1891:107-109), Shufeldt (1890:263-286), Palmgren (1949:194-195) M. complexus— Boas (1929:189-193) M. biventer cervicis M. biventer cervicis— Shufeldt (1890:270-272), Gadow (1891:107-109), Boas (1929:161-164) M. biventer— Palmgren (1949:194) M. splenitis capitis and M. splenitis accessorius M. rectus capitis posticus major — Shufeldt (1890:268-270) M. rectus capitis posticus — Gadow (1891:112) M. splenius capitis— Boas (1929:164-169), Palmgren (1949:194-195) M. depressor iimndibulae M. biventer maxillae— Shufeldt (1890:18-19) M. digastricus s. depressor mandibulae — Gadow (1891:318-319) M. depressor mandibulae— Edgeworth (1935:109), Hofer (1950) M. rectus capitis lateralis M. rectus capitis anticus minor — Shufeldt (1890:265-266) M. rectus capitis anticus minor s. lateralis — Gadow (1891:120-121, pi. 18a) M. rectus capitis lateralis— Boas (1929:194), Palmgren (1949:202) M. rectus capitis superior M. rectus capitis lateralis plus M. trachelo-mastoideus — Shufeldt (1890: 289-290). Shufeldt must have been partly in error in thinking that the M. longus lateralis cervicis et capitis of Gadow was the same as these muscles of Shufeldt's description. These muscles may correspond in part to the capitis part of Gadow's muscle. The remainder of M. longus lateralis cervicis et capitis compares well with the M. obliquus colli slips described and figured by Shufeldt. part M. spinalis cervicis plus part M. longus lateralis cervicis et capitis — Gadow (1891:110, 116-117) M. rectus capitis superior — Boas (1929:195-196) M. rectus capitis ventralis lateral part not described: ?part M. flexor capitis inferior — Shufeldt (1890:267-268) part M. rectus capitis anticus major s. medialis — Gadow (1891:120, pi. 18b) M. rectus capitis ventralis— Boas (1929:194-195), Palmgren (1949: 202-203) medial part part M. flexor capitis inferior— Shufeldt (1890:267-268) b THE MYOLOGY OF THE WHOOPING CRANE part M. rectus capitis anticus major s. medialis — Gadow (1891:120) M. rectus capitis ventralis — Boas (1929:194-195), Palmgren (1949: 202-203) M. flexor colli brevis ?part M. rectus capitis lateralis— Shufeldt (1890:289) ? M. lateralis colli— Gadow (1891:119) M. flexor colli brevis— Boas (1929:196-197) M. flexor colli profundus ?part M. longus colli (inferior oblique part?)— Shufeldt (1890:287-288) part M. longus colli anticus— Gadow (1891:118-119) M. flexor colli profundus— Boas (1929:197) M. adductor mandibulae externus superficialis part M. temporal— Shufeldt (1890:16) parts 1 and 2 M. temporalis— Gadow (1891:320-321) part M. adductor mandibulae externus — Edge worth (1935:58-60) M. adductor mandibulae externus superficialis — Lakjer (1926:45-46), Hofer (1950:438-468, fig. 15, A. e. sf. and A. e. sf. b.) M. adductor mandibulae externus profundus part M. temporal— Shufeldt (1890:16) ?part 3 M. temporalis— Gadow (1891:322) part M. adductor mandibulae externus — Edgeworth (1935:58-60) M. adductor mandibulae externus profundus — Lakjer (1926:46), Hofer (1950:464) M. adductor mandibulae medius part M. temporal plus M. pterygoideus externus — Shufeldt (1890:16, 20-21) M. ethmo-maxillaris plus M. quadrato-maxillaris — Gadow (1891: 322-323) ? M. adductor mandibulae posterior plus ? M. pseudotemporalis profun- dus— Lakjer (1926:54-55, 63-65) part M. adductor mandibulae medius — Edgeworth (1935:58-59) ?deep part M. pseudotemporalis (M. quadrato-mandibularis ) — Hofer (1950:478) M. adductor mandibulae externus medialis part M. temporal plus M. masseter — Shufeldt (1890:16) parts 1, 2 and ?3 M. temporalis— Gadow (1891:320-322) part M. adductor mandibulae externus — Edgeworth (1935:58-60) M. adductor mandibulae externus medialis — Lakjer (1926:46), Hofer (1950:438-468) M. pseudotemporalis part M. temporal— Shufeldt (1890:16) M. spheno-maxillaris — Gadow (1891:323) M. pseudotemporalis superficialis — Lakjer (1926:63-65) part M. adductor mandibulae medius — Edgeworth (1935:277) ? superficial part M. pseudotemporalis — Hofer (1950:468-477) M. pseudotemporalis bulbi M. pseudotemporalis bulbi — Lakjer (1926:figs. 124, 127) M. pterygoideus ventralis part M. pterygoideus interims — Shufeldt (1890:20) part Mm. pterygoidei— Gadow (1891:323-325) ventral part M. adductor mandibulae interims — Edgeworth (1935:58, figs. 605c, 607) M. pterygoideus ventralis— Lakjer (1926:65-67), Hofer (1950:481-495) MUSCLES OF THE SKULL AND JAWS 9 M. pterygoideus dorsalis part M. pterygoideus interims — Shufeldt (1890:20) part Mm. pterygoidei— Gadow (1891:323-325) dorsal part M. adductor mandibulae interims — Edgeworth (1935:58, fig. 605c) M. pterygoideus dorsalis— Lakjer (1926:65-67), Hofer (1950:481-495) M. protractor pterygoideus ?part M. entotympanicus— Shufeldt (1890:19-20) part 4b M. temporalis (M. orbito-ptervgoideus ) — Gadow (1891: 319-323, pi. 27 fig. 4) M. protractor pterygoideus— Lakjer (1926:23-25), Hofer (1950: 432-438) part M. spheno-pterygo-quadratus — Edgeworth (1935:57) M. protractor quadratus ?part M. entotympanicus— Shufeldt (1890:19-20) part 4a M. temporalis (M. orbito-quadratus ) — Gadow (1891:319-323, pi. 27 fig. 4) M. protractor quadratus— Lakjer (1926:23-25), Hofer (1950:432-438) part M. spheno-pterygo-quadratus — Edgeworth (1935:57) M. dermo-temporalis Figure 1 shows M. dermo-temp. arising from the same fascial layer that forms part of the origin of M. depress, mandib. This fascia is attached to the outer face of the opisthotic process, posterior and dorsal to the external auditory meatus. From the origin the muscle, which is about 3.5 centimeters in length, courses postero-dorsad across the anterior part of M. rectus cap. lat., the most dorsal part of M. geniohy., and the side of the middle of the length of the caput part of M. cucullaris to insert on the skin near the mid-dorsal line over the articulation between the second and third cervical vertebrae. M. cucullaris, caput part It may be observed in figures 1 and 4 that the cephalic part of M. cu- cullaris lies dorsally on the neck just posterior to the head but passes postero-ventrad to assume a lateral and even a ventral position at the posterior end of cervical vertebra number 4. It is a thin sheet of muscle with much aponeurotic connection to the underlying muscles and, in the dorsal midline, to its counterpart of the opposite side. Origin. — Although there is much fascial connection posteriorly, par- ticularly in the dorsal half of the neck, the primary origin is from the diapophysis of the fourth cervical vertebra. It is difficult to be more spe- cific regarding the origin because of the intimate relationship of fascial elements in this area. Insertion. — Anteriorly the muscle attaches to the most superficial part of the occipital crest from the midline laterad. The medial part of the insertion is immediately superficial to the insertion of M. biventer cerv., and the lateral part to the insertion of M. splenius cap. (fig. 4). £ T3 a 3 CO I O MUSCLES OF THE SKULL AND JAWS 11 M. bi venter cervicis The long, attenuated muscle is fleshy in the anterior 4 centimeters of its length but at the posterior end of the second cervical vertebra a long, thin tendon is formed (fig. 3). The tendon goes posteriorly on the neck just lateral to the midline. Anteriorly the muscle lies between the sheets of muscle making up the caput part of M. cucullaris and M. splenitis cap. In the middle of the length of the twelfth cervical vertebra the tendon becomes fleshy and forms a belly of the same proportions as the anterior belly. The posterior belly extends to the middle of the fifteenth vertebra, where a tendon is again formed. Origin. — The posterior end of the tendon just mentioned arises from the anterior edge of the neural crest of the sixteenth cervical vertebra and is closely associated with other muscles attaching here. Insertion. — Tendinous and fleshy insertion is made on the occipital crest just lateral to the midline and deep to the insertion of the cephalic part of M. cucullaris; it is about 0.5 centimeter wide (fig. 4). insert., add. mandib ext. superf., superf. slip orig., pseudotemp. orig., depress, palp. orig., add. mandib. ext. medialis orig., add. mandib. ext. superf., deep slip orig., pseudotemp. bulbi orig. , add. mandib. ext. prof., rostral slip orig., depress, mandib. insert., rectus cap. lat. pt. insert., add. mandib. medius, lat. pt. insert., add. mandib ext. prof., rostral slip insert., add. mandib ext. prof., caudal slip ear quadrate pt. insert., add. mandib. medius brigs. , add. mandib. medius + add. mandib. ext. prof., caudal slip Fig. 2. Diagram of the muscular attachments on the skull and lower jaw. M. splenius capitis The thick, triangular belly lies on the dorso-lateral part of the vertebral column over the atlas and axis (figs. 1, 3). It is, for the most part, covered by the caput part of M. cucullaris and M. bi venter cerv. The antero- ventral portion of the muscle lies just beneath the insertion of M. rectus cap. lat., while the postero-lateral edge covers parts of Mm. splenius access, and rectus cap. sup. Origin. — There is fleshy and tendinous origin from the side of the neural crest of the axis and from fascia overlying the atlas and extend- ing to the foramen magnum. On the axis the origin is dorsal to the middle 12 THE MYOLOGY OF THE WHOOPING CRANE of the belly of M. splenius access, and to the Mm. interspinales arising from the antero-ventral part of the crest (fig. 3 ) . Insertion. — A wide line of fleshy insertion (fig. 4) is present in the dorsal part of the occipital region and extends ventro-laterally on to the base of the opisthotic process. At its ventral end the insertion is medial to the insertion of M. rectus cap. lat. and the dorso-lateral part of the origin of M. depress, mandib. and is almost continuous with the heavy, medial origin of this same muscle. M. splenius accessorius Although the muscle does not connect directly with the skull, it is in- cluded here because it is apparently a part of the splenius complex (figs. 3, 5). It is a flat band which is covered anteriorly by M. splenius cap. and which overlies the anterior end of the M. spinalis cerv. complex; it runs from the third cervical vertebra to the atlas. The dorsal edges of the second and third fasciculi of M. rectus cap. sup. lie under the ventral border of the anterior half of M. splenius access. Origin. — The lateral surface of the neural crest of the third cervical vertebra provides fleshy and tendinous origin. Insertion. — The insertion is primarily tendinous on the posterior sur- face of the most ventral and lateral extent of the atlas (fig. 5), and con- tiguous with the ventral edge of the interspinales muscles. M. depressor mandibulae In figure 1 the muscle may be seen to lie across the suspension of the lower jaw; the medial part of the muscle is best illustrated in figure 7. Posteriorly and distally the lateral and medial parts are inseparably fused, but the inserting tendon of M. rectus cap. lat. forms the separation in the dorsal part. Deep to the medial part is the ligamentum mandibulae. The antero-ventral edge is in contact with M. pteryg. vent., and M. stylohy. arises just anterior to the anterior edge of the belly of M. de- press, mandib. Above the origin of M. stylohy., M. depress, mandib. is separated from the external auditory meatus only by the membrane lining this canal. It would seem that any swelling of the belly, as when the muscle contracts or the posterior end of the mandible arcs dorsad, would tend to close the opening of the ear. The dorsal fascial part of the lateral portion is in part covered by M. dermo-temp. Origin. — The extent of the origin from the postero-lateral area of the occipital region and the posterior face of the opisthotic process may be observed in figures 2 and 4. On the lateral surface of the process the origin is tendinous and fleshy, but it goes dorsad as a tendinous apo- neurosis to the level of the deep slip of M. add. mandib. ext. superf. From the most ventral and medial tip of the opisthotic process, a strong tendon forms a major part of the origin of the deeper, medial portion of the muscle; in fact, many of the tendinous fibers pass through the fleshy belly and thus go from origin to insertion and serve as a ligament. MUSCLES OF THE SKULL AND JAWS 13 Insertion. — The superficial and most ventral part of the insertion is tendinous on the postero-ventral corner of the lateral surface of the mandible. The primary insertion is fleshy on the entire area of the pos- terior end of the mandible, bordered anteriorly by the posterior end of M. pteryg. vent. (fig. 1). M. rectus capitis lateralis The asymmetry visible in the Mm. recti cap. vent, is not so evident in the present muscles. On the left side the belly of M. rectus cap. lat. is intimately connected with the deep lateral edge of the belly of M. rectus cap. vent., probably as a secondary effect of the asymmetry of the latter pseudotemp. add. mondib. ext. superf., deep slip biventer cerv. >. j splenitis cop. splenius access. odd. mandib. medius, lot. pt. add. mandib ext. prof., rostral slip rectus cap. rectus cap. lot. vent., med. pt. rectus cop. sup. flex, colli brevis- longus colli intertransverse™ Fig. 3. Lateral view of a second layer of muscles of the head and the anterior vertebral region. muscle. On the right these two recti muscles are separate and distinct. In lateral view the single slip of M. rectus cap. lat. emerges from the neck musculature just dorsal to the lateral part of M. rectus cap. vent. (figs. 1, 3, 7) and ventral to the various slips of M. rectus cap. sup. Origin. — There is fleshy and fascial origin from the ventro-lateral cor- ners of the hypopophyses of cervical vertebrae 3 and 4. Insertion. — A heavy tendon attaches to the posterior face of the base of the opisthotic process, deep and posterior to the lateral origin of M. depress, mandib. (figs. 2, 3, 4) and superficial in part to the most lateral edge of M. splenius cap. M. rectus capitis superior The muscle complex to be considered consists of five different fasciculi which arise from the first five cervical vertebrae and extend to the ventro-lateral region of the head (figs. 1, 3, 5, 6, 7). They are arranged 14 THE MYOLOGY OF THE WHOOPING CRANE serially so that the most dorsal goes anteriorly from the atlas and the most ventral and posterior slip comes from the fifth vertebra. From this description it is apparent that the slips increase in length from anterior to posterior in the series. In lateral and dorsal view the bundles are var- iously covered by M. splenius cap., the caput part of M. cucullaris, and M. rectus cap. lat. On the ventral side they are deep to the latter muscle and to the lateral part of M. rectus cap. vent. Origin. — Fasciculus number 1, the most anterior and dorsal, arises from the most lateral extent of the anterior surface of the postzygopophyseal area of the atlas. Number 2 comes from the same part of the postzygo- pophyseal process of the axis, but its origin goes forward on a mid-lateral line on the body of this vertebra. The same part of vertebra 3 gives rise to slip 3 which is twice as large as slips 2 and 4; the origin is completely tendinous and continues anteriorly across the joint between vertebrae 2 and 3. There is fleshy origin from the ventro-lateral corner of the centrum of vertebra 2 and beneath the origin of the second part of the muscle complex. Part number 4 has fleshy and tendinous origin from the lateral tip of the transverse process of vertebra 4; the origin is closely intercon- nected with the fascia giving rise to the Mm. intertransversarii. Bundle 5 arises fleshily from the anterior edges of the posterior zygopophyseal proc- esses of vertebrae 3 and 4 and from a mid-lateral line on the centrum of vertebra 4; there is also tendinous origin from the anterior edge of the transverse process of vertebra 5. The deep surface of this fifth part of M. rectus cap. sup. gives off a small slip antero-mediad. Insertion. — The four most anterior slips insert tendinously and in com- mon on the lateral three-fourths of the length of the posterior edge of the basitemporal plate (figs. 4, 8). The fifth and by far the largest slip inserts tendinously on the most antero-lateral corner of the axis and the postero- lateral aspect of the atlas. There is heavy fascia covering the articulation between the first two cervical vertebrae and attaching anteriorly to the base of the skull; the fifth slip uses this as part of its insertion. Hence the functional insertion of the slip is at least in part on the middle of the pos- terior edge of the basitemporal plate. M. rectus capitis ventralis The muscles of the two sides are not symmetrically arranged; on each side of the ventral aspect of the neck the muscle consists of a medial and a lateral part. On the left side the posterior end of the lateral portion extends fleshily to the caudal end of the fifth cervical vertebra; on the right side it goes only to the fourth vertebra. This asymmetry is also visible in the medial parts of the muscles; the left goes to the fourth vertebra and the right to the third. The variation between sides is appar- ently correlated with the position of the trachea. Superficial to the caudal end of the right M. rectus cap. vent, the trachea moves from its position on the right side of the neck to a ventral location (fig. 9 ) . MUSCLES OF THE SKULL AND JAWS 15 In figure 7 it may be observed that the lateral part is superficial to M. rectus cap. lat. and is separated from its opposite member by the paired veins; this separation is only superficial, for along the posterior two-thirds of their dorsal edges the muscles meet in the midline. Where the two medial parts are side by side they are inseparable. Although in their posterior parts the lateral and medial slips are distinct, they are more or less fused opposite and anterior to the region of M. depress, mandib. (figs. 1,3,7). Origin. — The left lateral part comes from the hypopophyses of cervical vertebrae 4 and 5 (sometimes 6 as well) and from the midventral line of the centra between these hypopophyses. The anterior end of this line is continuous with the posterior end of the line of origin of the medial part, which latter origin continues on this line to the base of the skull. The right lateral part takes its principal origin from the hypopophysis of vertebra 4 but may extend on to number 5. The medial part on this side is similar in its origin to that on the left except that it goes posteriorly only as far as the hypopophysis of the third vertebra. Insertion. — The lateral parts of this pair of muscles insert tendinously on the posterior surface of the occipital process (fig. 8), and the medial parts attach fleshily to the entire area of the basitemporal plate (figs. 7, 8). There may be tendinous insertion at the apex of the basitemporal plate. M. flexor colli brevis Topographically the muscle could be considered as slips of the M. rectus cap. sup. complex (figs. 1, 3, 5, 6). However, its anterior end does not reach to the head. Consequently, functionally at least, it is a separate muscle. It lies posterior and ventral to the most posterior slip of the supe- rior rectus group and is just dorsal to the cephalic end of M. longus colli. In its passage antero-ventrally it traverses the most ventral and lateral parts of the Mm. intertransversarii present here. Origin. — The origin is in three parts. The most anterior comes from the ventro-lateral corner of the entire length of the axis, beneath the an- terior end of the posterior fasciculus of M. rectus cap. sup., and from the anterior end of the third cervical vertebra. Origin 2 is on the lateral end of the transverse process of the fifth vertebra, virtually in common with, but deep to, the origin of the posterior parts of M. rectus cap. sup. The last origin is tendinous from the end of the transverse process of the sixth vertebra and is superficial to the ventral edge of the Mm. intertrans- versarii (fig. 6). Insertion. — The most anterior insertion is fleshy on the dorso-lateral edge of the anterior end of the most posterior slip of M. rectus cap. sup., which in turn attaches primarily to the atlas. The other slips of this flexor insert, one above the other, on the most posterior area of the transverse process of the third cervical vertebra. At its insertion the more posterior 16 THE MYOLOGY OF THE WHOOPING CRANE of these parts is fused with the anterior part of M. longus colli (fig. 6). M. flexor colli profundus This group of fasciculi (fig. 6) has sometimes been considered a part of M. longus colli. It does in fact replace M. longus colli on vertebrae 2 and 3 and coexists with this muscle on vertebrae 4 and 5. There are six distinct bundles of fibers constituting M. flex, colli prof., which is the deepest of the ventral muscles in the anterior part of the neck. insert., biventer cerv. insert., cucullaris, caput pt. occipital ridge insert., splenitis cap. insert., rectus cap. lot. orig., depress, mandib. quadrate insert ' 4 sli P s rectus cap. sup. Fig. 4. Diagram of the muscular attachments on the posterior end of the skull. Origin. — The anterior part ( slip 1 ) arises fleshily from the lateral part of the antero-ventral surface of the transverse process of vertebra 3. Slip 2 comes from a more medial and posterior part of the same process (fig. 6). Number 3 takes fleshy origin from the antero-ventral edge of the transverse process of the fourth vertebra and from the ventro-lateral cor- ner of the centrum of the third vertebra. The fourth slip, counting from the anterior end of the complex, originates as a fleshy and tendinous belly from the transverse process and anterior part of the centrum of vertebra 5 and from the side of the posterior end of the centrum of the fourth vertebra. Bundles 5 and 6 come from the ventral surface of the antero- lateral corner of the sixth vertebra, and to a lesser degree from the same surface of the postero-lateral corner of vertebra 5 ( fig. 6 ) . Insertion. — Slips 1 and 2 insert fleshily on the ventral part of the ante- rior end of the axis ( fig. 6 ) ; the attachment of number 1 is dorso-anterior to that of number 2. Number 3 goes tendinously to the posterior end of the hypopophysis of the axis. Four inserts tendinously on the postero-lat- eral corner of the hypopophysis of the third cervical vertebra. Number 5 attaches to the same place on the fourth vertebra, in common with the second most anterior slip of M. longus colli. Slip 6 inserts on the same area of vertebra 5. M. adductor mandibulae externus superficialis The nomenclature of the muscles of the adductor and pterygoideus groups is in a state of vast confusion, despite the major studies by Lakjer MUSCLES OF THE SKULL AND JAWS 17 (1926), Edgeworth (1935), Fiedler (1951), and Hofer (1951). Because of interspecific variation and lack of agreement between previous work- ers it is virtually impossible to assign names with confidence. We agree with Beecher (1951:415) that "the jaw musculature appears confusing when fully labelled . . . ." We have not, with our few specimens, con- ducted any independent investigations of homologies, and we only use the existing names (pp. 7-9). The most superficial of the adductors is M. add. mandib. ext. superf., which has two parts — a superficial and a deep layer. The outer layer does not always cover the dorsal part of the deep layer ( fig. 1 ) , lies just be- neath and somewhat posterior to the eye, and is parallel and anterior to M. add. mandib. ext. prof. At its antero-ventral extent it is immediately anterior to the outer part of M. add. mandib. medius. The deep pinnate fasciculus of M. add. mandib. ext. superf. (figs. 1, 3) in some specimens is the most superficial muscle of the upper part of the temporal fossa; Mm. pseudotemp., add. mandib. ext. medialis, and add. mandib. ext. prof, are deep to it. In its distal part the muscle is covered by the superficial part of M. add. mandib. ext. superf. and by the lateral part of M. add. mandib. medius. Origin. — The superficial layer originates from the fascia overlying the middle of the length of the deep layer and from a tendon which passes beneath the postero-ventral part of the deep layer to attach to the pos- terior rim of the temporal fossa. The deep part comes fleshily from an extensive area of the dorso-posterior region of the temporal fossa ( fig. 2 ) . Insertion. — The superficial fasciculus inserts tendinously and fleshily on the dorso-lateral edge of the mandible for a distance of 1 centimeter, starting just anterior to the anterior edge of the dorsal part of the inser- tion of the external part of M. add. mandib. medius. (figs. 2, 7). This at- tachment continues forward, on the dorsal rim of the mandible, to the region of the junction of the maxillary and quadratojugal bones where it ends on the connective tissue in the corner of the mouth. Laterally the insertion is dorsal to the anterior part of the insertion of the external portion of M. add. mandib. medius. Immediately ventrad to the postorbital process of the skull, the bi- pinnate belly of the deep slip forms a calcified tendon (fig. 3) which inserts on the coronoid process of the mandible between the two layers of M. add. mandib. medius (fig. 5). The insertion is posterior to the in- sertion of the superficial slip. M. adductor mandibulae externus profundus The muscle has two parts — a rostral and a caudal (figs. 1, 3, 5). Other than the posterior part of M. add. mandib. medius (?M. add. mandib. post, of Lakjer, 1926) this is the most posterior of the external adductor muscles. It is posterior and in antero-ventral part deep to M. add. mandib. medius. The dorsal end of the rostral part is covered by the deep slip of 18 THE MYOLOGY OF THE WHOOPING CRANE M. add. mandib. ext. superf. and in turn completely covers the caudal part. The rostral slip is bipinnate (figs. 1, 3) and the caudal slip simple (fig- 5). Origin. — Figure 2 shows the fleshy origin of the rostral slip from the postero-ventral area of the temporal fossa and from the dorso-lateral sur- face of the orbital process of the quadrate. Beneath the fleshy origin there are several strong bands of calcified tendon which extend from origin to insertion; some of these come from the antero-dorsal part of the supra- meatic process. The anterior edge of the orbital process of the quadrate provides fleshy origin for the caudal slip (fig. 2); the area is limited to the ventral half of this edge, for the posterior slip of M. add. mandib. medius arises from the dorsal half and is continuous and inseparable from the dorsal end of the caudal part of this profundus muscle. Insertion. — The rostral slip inserts tendinously on the dorso-lateral corner of the mandible, beneath the middle of the orbital fossa, deep and dorsal to the insertion of the main, external body of M. add. mandib. medius, and anterior to the insertion of the caudal fasciculus. The pos- terior end of the line of attachment is 2 centimeters from the posterior end of the mandible. See figure 2 for an illustration of both insertions. M. adductor mandibulae medius As we understand the conformation of the muscle, it consists of a medial and a lateral part, which together make this the largest of the jaw adductors. The lateral part may be seen external to the mandible (figs. 1, 3, 7), and the medial slip is beneath the eye as the deepest of all adductors in this area (figs. 5, 7, 8). The lateral part is, in its dorsal half, deep to the superficial fasciculus of M. add. mandib. ext. superf. Its disto-anterior edge is in contact, on the outer surface of the mandible, with this superficial fasciculus; its posterior border is over the M. add. mandib. ext. prof. In some specimens the postero-ventral corner is in contact with the superficial part of M. pteryg. vent. The lateral and medial parts are separated on the dorsal ridge of the mandibular ramus by the insertions of both fasciculi of M. add. mandib. ext. superf. and by that of the rostral bundle of M. add. mandib. ext. prof. (figs. 2, 5). Origin. — A calcified tendon from the postero-ventral part of the squa- mosal bone, but primarily from the post-temporal process of this bone, constitutes the origin of the lateral part (fig. 3). The tendon is deep to the ventral edge of the deep part of M. add. mandib. ext. superf. and immediately dorsal and superficial to the upper edge of the rostral slip of M. add. mandib. ext. superf. The medial part arises fleshily from the dorsal part of the lateral face and from the anterior surface of the orbital process of the quadrate ( fig. 2 ) ; the medial area of this process provides some fleshy origin. The dorsal part of the fleshy origin is overlaid by MUSCLES OF THE SKULL AND JAWS 19 heavy fascia. Since M. pseudotemp. inserts on the dorso-medial edge of the medial part, it should probably be considered a part of the origin. Insertion. — The lateral part inserts directly on the external surface of the mandible by means of muscular fibers; the region of insertion in- cludes all that part of the mandible covered by the muscle in figures 1 and 3. (See also fig. 2). The medial part of M. add. mandib. medius at- 2 20 THE MYOLOGY OF THE WHOOPING CRANE taches fleshily to the inner side of the mandibular ramus in that depres- sion beginning posteriorly at the internal articular process and going an- teriorly to the region of the surangular. At its posterior end the insertion extends dorso-laterad on the mandible just anterior to the articular facets; this latter extension may correspond to the insertion of M. add. mandib. post, of Lakjer. In lateral aspect the wide, inserting tendon of M. pseudo- temp, crosses the medial part and attaches to the medial side of the mandible. M. adductor mandibulae externus medialis As may be seen in figure 5, this is the deepest of the muscles of the adductor group in the temporal fossa; it is superficial only to M. pseudo- temp, and to the origin of M. pseudotemp. bulbi (fig. 2). Origin. — It arises tendinously from a narrow line in the temporal fossa, between the dorso-posterior part of the origin of M. pseudotemp. and the antero-dorsal section of the origin of the deep slip of M. add. mandib. ext. superf. (fig. 2). Insertion. — At the postero-ventral corner of the orbital fossa the thin band of muscle becomes tendinous and inserts as a weak aponeurosis or dense fascia on the connective tissue covering the dorso-medial border of M. add. mandib. medius (fig. 5). M. pseudotemporalis Although this is the deepest of the muscles in the temporal fossa, the anterior corner of the dorsal end of its thick belly is visible superficially (figs. 1, 3). In cross-section the belly is triangular; at the ventral end of the post-orbital process the belly is crossed superficially by the belly of M. pseudotemp. bulbi. Edgeworth (1935:277) included M. pseudotemp. as part of his M. add. mandib. medius. However, in the Whooping Crane it is a very distinct muscle as Lakjer (1926:63-65) has indicated. We were not able to find the two parts described by Lakjer. Origin. — The origin is well depicted in figure 2; usually it is fleshy but in one instance aponeurotic origin was also found. Insertion. — At the postero-ventral corner of the eye, the heavy belly gives way to a strong, flat, calcified tendon which goes ventrad super- ficial to the medial part of M. add. mandib. medius (fig. 5). The tendon inserts on the middle of the width of the mandible, about 3 centimeters from the posterior end of the bone. Thus the insertion is covered medially by the insertion of the medial layer of M. add. mandib. medius. M. pseudotemporalis bulbi The thin band of M. pseudotemp. bulbi lies ventral to the post-orbital process, deep to M. add. mandib. ext. medialis and superficial to the middle of the belly of M. pseudotemp. (fig. 5). Origin. — The origin is fleshy and tendinous from the middle of the ventral part of the temporal fossa, posterior to the origin of M. pseudo- MUSCLES OF THE SKULL AND JAWS 21 temp., and deep to the anterior edge of the origin of the rostral slip of M. add. mandib. ext. prof. (fig. 2). Insertion. — There is fleshy insertion on the fascia beneath the postero- ventral corner of the lacrimal gland (fig. 5). A second insertion, tendi- nous, comes from the muscle immediately ventral to the lacrimal gland and attaches to the connective tissue at the postero-ventral corner of the eye. ■4 — atlas rectus cop. sup., I ~4 — axis post, slip ~^____^ -JM flex, colli brevis . jr fi vert. no. 3 3 V \ j\ flex, colli prof rectus cop. sup., cut end post. slip~i» 1 V { ■ I MSfflf vert. no. 4 flex, colli brevis s, § k \wjm— ;=»- f lex. colli prof wc 1 ml MM *— — vert, no. 5 iiri'iii longus colli— = intertronsversarii < \ \ W& vert. no. 6 Fig. 6. Ventral view of the deep muscles or the anterior vertebral region. M. pterygoideus ventralis Edgeworth ( 1935 ) synonymized all of Lakjer's pterygoideus muscles with the muscle he called M. adductor mandibulae internus. Embryo- logically the entire muscle mass may be a single unit but, as Lakjer has shown, it breaks into a number of distinct, well-defined muscles which are variously developed in the different groups of vertebrates and which show major differences between some related species. It is of course easiest to combine all these into one unit, but this makes descriptive treatment of the variations an arduous task and leads to a glossing-over of the quite manifest diversities and separate entities of this complex of muscles. We have, therefore, retained as a matter of convenience the terms — M. pterygoideus ventralis and M. pterygoideus dorsalis. And since these pterygoideus muscles are composed of several fasciculi in the Whooping Crane, we designate these subdivisions as lateral and medial parts. The pterygoid muscles are in three layers in the Whooping Crane — a 22 THE MYOLOGY OF THE WHOOPING CRANE ventral, which is itself in two layers, and a dorsal stratum. The superficial ventral layer is undivided, but the deep, ventral part exists as lateral and medial slips. The dorsal layer is similarly separated into lateral and medial fasciculi; this sheet is here designated as M. pteryg. dors. Both ventral sheets are called M. pteryg. vent. In figure 7 both layers of M. pteryg. vent, are shown, as is the division of the deep layer into lateral and medial parts. The superficial layer is the outermost muscle of the ventral surface, crossed only by the small belly of M. stylohy. and a branch of the facialis vein. Its posterior end is marked by contact with M. depress, mandib. (fig. 1). The postero-medial os pal mandib quadratojuqol pteryg. dors. pteryg. vent., deep rectus cap. sup. int. jugular vein add. mandib. ext. superf., superf. pt. add. mandib. medius, med. pt. add. mandib. medius , lot. pt. branch, faciolis vein stylohyoideus pteryg. vent., superf. rectus cap. vent., med. pt. depress, mandib. rectus cap. lot. rectus cap. vent., med. pt. lot. pts. rectus cap. sup. 2 post, slips flex, colli brevis 5th. vert. 6th. vert. longus colli Intertransversarii FlG. 7. Ventral view of the muscles of the jaw and the anterior vertebral region. On the left side of the jaw region the superficial layer of M. pteryg. vent, and M. depress, mandib. have been removed. Note the asymmetry of M. rectus cap. vent. MUSCLES OF THE SKULL AND JAWS 23 edge overlies the anterior end of the medial bundle of M. rectus cap. vent. Anteriorly it covers the posterior two-thirds of the length of the os palatine and all of the second and more dorsal layer of M. pteryg. vent. After removal of the superficial sheet, which is strongly bipinnate on its deep aspect, the two fasciculi of the deeper layer are evident ( fig. 7 ) . The lateral slip extends forward from the inner side of the posterior end of the mandible; it is superficial to the insertion of the lateral part of M. rectus cap. vent, on the occipital process on the lateral area of the basitemporal plate. Along the ventro-lateral edge of the wing of the palatine, it is superficial to the parts of M. pteryg. dors. The medial fasciculus of the deep layer of M. pteryg. vent, goes antero-mediad from the posterior end of the mandible, bordered medially by the anterior end of the medial part of M. rectus cap. vent, and laterally being superficial to the insertion of the medial part of M. pteryg. dors. (fig. 7). Origin. — The superficial layer is overlaid anteriorly by a strong, silvery aponeurosis which forms part of the origin from the ventral area of the palatine, and particularly from the medial edge. Deep to this aponeurotic origin there is strong fleshy origin from the entire ventral concavity of the palatine. The lateral part of the deep sheet arises tendinously from the posterior half of the lateral corner of the palatal wing; the medial part of this layer comes fleshily from the posterior end of the palatine (fig. 7) and passes posteriorly over M. protract, pteryg. Insertion. — The superficial muscle attaches fleshily on the outer face of the posterior part of the mandible, on all that part of this bone covered by the muscle in figure 1. Medial to this insertion is a thin line of ten- dinous insertion going dorsad on the inner aspect of the mandible and between the origin of the lateral, deep fasciculus and the medial part of the insertion of M. depress, mandib. The lateral, deep fasciculus of M. pteryg. vent, inserts fleshily on the medial face of the mandible in an area delimited posteriorly by the in- sertion of M. depress, mandib., ventrally by the ventral edge of the man- dible, and dorsally in its anterior extent by the ventral edge of the lateral slip of M. pteryg. dors. The medial bundle of the deep layer goes to the internal articular process as mixed fleshy and tendinous fibers (fig. 7). M. pterygoideus dorsalis The two slips comprising the muscle are illustrated in figure 7; the medial one is best shown in figure 8. The lateral fasciculus lies antero- dorsad of the lateral part of M. pteryg. vent.; its dorsal surface is in con- tact with the medial aspect of the medial part of M. add. mandib. medius. The more medial slip of M. pteryg. dors, is deep to the second layer of M. pteryg. vent, and is in part superficial to M. pteryg. protract, (fig. 8). Origin. — The lateral part has tendinous and fleshy origin from the en- tire dcrso-lateral surface of the palatine as far anterior as the most ante- rior part of the origin of the superficial layer of M. pteryg. vent, shown in 24 THE MYOLOGY OF THE WHOOPING CRANE figure 7. At this point, which is 6 or 7 centimeters from the posterior end of the palatine, the origin continues dorso-mediad and ends about 12 millimeters above the most ventral border of the palatal alae. The medial slip of M. pteryg. dors, arises tendinously and fleshily from the ventral and antero-lateral edges or surfaces of the anterior end of the os pterygoid ( fig. 8 ) . The strong tendon shown overlying the insertion is superficial only. Insertion. — The lateral belly sends a partly calcified tendon, 1 centi- meter wide, to the medial face of the mandible. This site is anterior to the insertion of the medial part of this same muscle, is immediately ventral to the medial insertion of M. add. mandib. medius, and is covered posteriorly by the insertion of the deep, lateral part of M. pteryg. vent, (fig. 7). The medial slip attaches fleshily to the medial aspect of the posterior end of the mandible, and deep to all other attachments; its anterior border is marked by the posterior end of the insertion of the medial part of M. add. mandib. medius (fig. 8). os mandib insert., rectus cap. vent., lot. pt. ext. aud. meatus os pal. add. mandib. medius, med. pt. os pteryg. pteryg. protract, pteryg. dorsalis , med. pt. insert., rectus cap. vent., med. pt. insert., 4 slips, rectus cap. sup. Fig. 8. Ventral view of the deep muscles of the posterior end of the skull and jaw. M. protractor pterygoideus Figure 8 shows some of the relationships of the muscle. It is a small belly lying along the medial side of the os pterygoid and between this bone and the antero-lateral border of the basitemporal plate. It is largely covered by the medial slip of M. pteryg. dors, and by the medial slip of the second layer of M. pteryg. vent. Origin. — The posterior end of the belly arises, primarily as fleshy fibers MUSCLES OF THE SKULL AND JAWS 20 with a few superficial tendinous fibers interposed, from the most lateral protuberance of the basitemporal plate, which point lies at the level of the posterior end of the quadrate. Insertion. — There is a fleshy insertion, with some superficial fascial connection, on the medial and dorsal surfaces of the anterior third of the length of the pterygoid bone. M. protractor quadratus The very thin belly of this muscle, which is only 8 millimeters wide, comes from the antero-ventral edge of the temporal fossa and from the postero-ventral part of the orbital fossa ( fig. 2 ) . It inserts on the posterior edge of the most medial part of the orbital process of the quadrate. The insertion is thus opposite the posterior part of the quadrate origin of the rostral slip of M. add. mandib. ext. prof. The anterior part of the muscle is immediately deep to the heavy belly of M. pseudotemp. Muscles of the Tongue Region M. constrictor colli ? M. digastric in pt. or M. platysma myoides — Shufeldt (1890:6-7, 21-22) pt. M. cucullaris or M. constrictor colli— Gadow (1891:214-216, 306) M. intermandibularis M. mylohyoideus— Shufeldt (1890:24-26), Moller (1930:670, 691, 709) M. mylo-hyoideus ant.— Gadow (1891:304-307), Mudge (1903:247-257) M. intermandibularis — Edgeworth (1935:61) M. geniohyoideus M. genio-hyoideus— Shufeldt (1890:27), Gadow (1891:313), Mudge (1903:261-262) M. kerato-mandibularis— Moller (1930:669, 692, 708) M. branchiomandibularis — Edgeworth (1935:61) M. sttjlohyoideus M. stylohyoideus— Shufeldt (1890:26-27), Gadow (1891:305-307), Mudge (1903:253-257) ant. pt. M. mylo-hyoideus post. — Gadow and Mudge (loc. cit.) M. hyo-mandibularis lat.— Moller (1930:670, 691, 710) M. gularis— Edgeworth (1935:109, 281-282) M. genio glossus M. genio-glossus— Gadow (1891:314), Mudge (1903:262), Moller (1931: 119, fig. 9) M. dermoglossus — new name M. ceratoglossus — lateralis and inferior (superior absent in G. americana) M. cerato-glossus— Shufeldt (1890:30-33), three parts Gadow (1891: 315-316) and Mudge (1903:214-232) M. kerato-hyoideus— Moller (1930:671, 692, 710) M. hypoglossus rectus pt. M. depressor glossus — Shufeldt (1890:30) M. hypoglossus rectus— Gadow (1891:317), Mudge (1903:246-247) M. hypoglossns obliquus pt. M. depressor glossus — Shufeldt (1890:30) M. hypoglossus obliquus— Gadow (1891:317), Mudge (1903:246-247) M. thyroglossns med. fibers M. sterno-hyoideus— Shufeldt (1890:29-30) M. thyreo-glossus— Gadow (1891:309) M. thyroglossus— Mudge (1903:235-245) M. thyrohyoideus lat. fibers M. sterno-hyoideus— Shufeldt (1890:29-30) M. thyreo-hyoideus— Gadow (1891:307-312) M. thyrohyoideus plus accessorius — Mudge (1903:232-234) M. tracheohyoideus ant. pt. M. cleido-tracheales— Shufeldt (1890:9-10) M. tracheo-hyoideus— Gadow (1891:307-312), Moller (1930:671, 692, 710) pt. M. sterno-hyoideus— Mudge (1903:258-261) 26 MUSCLES OF THE TONGUE REGION 27 M. tracheolaryngeus superior ant. pt. M. tracheo-lateralis— Shufeldt (1890:47-48) M. tracheo-laryngeus superior — Gadow (1891:309) M. tracheolaryngeus inferior post. pt. M. tracheo-lateralis— Shufeldt (1890:47-48) M. tracheo-laryngeus inferior — Gadow (1891:309) M. sternotrachealis M. sterno-trachealis— Shufeldt (1890:49-52), Gadow (1891:729-730) M. thyroarytenoideus M. thyreo-arytenoideus— Shufeldt (1890:45-47) M. apertor laryngis — Gadow (1891:718) M. dilatator laryngis— Edgeworth (1935:285,440) M. constrictor glottidis M. constrictor glottidis— Shufeldt (1890:45) M. sphincter laryngis — Gadow (1891:718) M. constrictor larvngis (dorsal portion) or M. constrictor dorsalis — Edgeworth (1935:285, 440) M. serpi-hyoideus of Gadow (1891:305-307) and Mudge (1903:253-257) is absent in the Whooping Crane, as is M. cerato-hyoideus of Shufeldt (1890: 27-29), Gadow (1891:316), and Mudge (1903:262-263) M. constrictor colli and M. intermandibularis Apparently the only remaining part of the ventral constrictor sheet in the Whooping Crane is represented by a thick aponeurosis having only a few contractile fibers. The aponeurotic layer lies between the posterior ends of the mandibles and extends forward nearly to the base of the tongue. It goes posteriorly to the level of the 6th or 7th cervical vertebra and there blends in with the fascia around the trachea and the ventro- lateral part of the cervical musculature. The anterior edge of the part corresponding to M. constrictor colli is marked by the posterior end of the basihyal bone. The few contractile fibers present are in a transverse band across the posterior half of the urohyal. Another diffuse band occurs across the anterior half of the length of the basihyal and probably represents the posterior edge of a vestigial M. intermandib. M. stylohy. (figs. 1, 7, 10), which is also a derivative of this primitive constrictor sheet of muscle, is a distinct muscle and will be described shortly. It seemingly is the remainder of the sheet lying between M. con- strictor colli and M. intermandib. On either side the fibers of M. constrictor colli arise from the postero- ventral part of the mandible and from the fascia which overlies the in- sertion of M. depress, mandib. and is just postero-ventral to the origin of M. stylohy. The fasciculus here termed M. intermandib. attaches to fascia about 2 centimeters antero-ventrad of the origin of M. stylohy. M. geniohyoideus This is a large band of muscle which extends from the posterior end of the epibranchial cartilage to the inner surface of the mandible. In the Whooping Crane it consists of but one fasciculus (figs. 1, 9, 10) which 28 THE MYOLOGY OF THE WHOOPING CRANE has, in the middle of its length, some interconnection with M. dermogl. in one of two specimens. Origin. — There is fleshy origin from the entire circumference of the trachea Fig. 9. Dorsal view of the tongue and the floor of the pharynx. The stippled area represents a cut edge of the wall. MUSCLES OF THE TONGUE REGION 29 epibranchial cartilage and from the dorsal and lateral surfaces of the posterior half of the length of the ceratohyal. Because of the variable development of the posterior extent of the epibranchial and ceratohyal, between specimens and even between the two sides of the same individ- ual, the posterior part of the origin of M. geniohy. is also variable. The greatest development of the horn of the hyoid apparatus is shown in figure 1; in the other extreme, the posterior end barely reaches the level of the postero-dorsal corner of the mandible. Insertion. — From the anterior end of its origin the muscle goes ante- riorly and somewhat laterally to insert fleshily on the inner surface of the mandible. This attachment is opposite the basihyal, or about 7 centi- meters anterior to the posterior end of the mandible. The anterior end of the insertion is marked by the most anterior end of the insertion of M. add. mandib. medius on the lateral surface of the mandible. M. stylohyoideus The band of muscle termed M. stylohy. here represents the anterior part of the posterior mylohyoideus sheet. The posterior part of this sheet, termed M. serpi-hyoideus by several authors (see page 27), could not be found in the Whooping Crane. M. stylohy. is a thin and narrow muscle lying superficially on the lateral face of the posterior part of the jaw and on the ventral surface of M. pteryg. vent. It crosses M. geniohy. and goes anteriorly alongside the ceratohyal bone ( fig. 1 ) . Origin. — The disto-anterior part of the opisthotic process (fig. 1) gives tendinous origin primarily, while there is strong fleshy and tendinous -origin from the middle of the postero-lateral corner of the mandible. Insertion. — The fleshy and fascial attachment is to the most antero- lateral surface of the ceratohyal. The anterior end of the insertion is marked by the articulation between the ceratohyal and basihyal bones (fig. 10).' M. genioglossus This muscle is a fleshy, widely triangular body which in ventral view is covered by M. geniohy., by M. stylohy., and by M. dermogl. In figure 10, M. geniohy. has been cut and pulled laterally. Origin. — There is a fleshy origin from the inner side of the mandible, dorsal to the middle of the width of the mandible. The site of the origin is dorsal to the mandibular attachment of M. geniohy. Insertion. — From this relatively short and narrow line of origin the muscle fans out as it goes ventro-mediad. Posterior to the entoglossum there is fleshy insertion on the tissues forming the floor of the mouth. The insertion continues anteriorly from the base of the entoglossum for one- half the length of this structure. Anterior to M. hypogl. obliq. the muscles of the two sides meet in the ventral midline of the entoglossum ( fig. 10 ) , 30 THE MYOLOGY OF THE WHOOPING CRANE hypoglossus rectus cut tendon cerotoglossus inf., lot. pt. hypoglossus obliquus bosihyal cerotoglossus inf., med. pts. urohyal dermoglossus genioglossus cut end stylohyoideus thyroglossus cricoid cart cerotoglossus inf., lot. pt. cerotoglossus lot. cerotoglossus inf., post. pt. geniohyoideus thyrohyoideus access, pt. trocheohyoideus tracheolaryngeus superior Fig. 10. Ventral view of the musculature of the tongue and the anterior part of the trachea. covering M. hypogl. rectus and inserting on the entoglossum. Throughout its length the insertion is in intimate contact with the floor of the mouth. M. dermoglossus We have been unable to find in the literature any muscle that is topo- graphically similar to this one, and because we were unable to determine its innervation in our specimens, we have simply used the descriptive name, M. dermoglossus (fig. 10). Judging from its position and insertion, the muscle may correspond to a superior slip of M. ceratogl., which has moved its origin from the ceratohyal bone to the skin and connective tissue immediately surrounding this bone. The absence of a true M. MUSCLES OF THE TONGUE REGION 31 ceratogl. sup. in the Whooping Crane might be further indicative of this interpretation. Origin. — The fascia on the external surface of the side of the pharynx, dorsal to the ceratohyal and medial to the middle of the length of the belly of M. geniohy., gives rise to the rather indistinct lateral end of the muscle. Insertion. — The fibers go antero-mediad, but mostly anteriorly, to insert as mixed fleshy and fascial fibers on the dorso-lateral corner of the an- terior end of the basihyal. This location is lateral and anterior to the in- sertion of M. thyrohy. and deep and medial to the lateral part of the insertion of M. hypogl. obliq. M. ceratoglossus lateralis Figure 10 shows the belly of this muscle paralleling and bordering the lateral side of the anterior half of the length of the ceratohyal. The anterior part of it is covered by the lateral and medial parts of M. cera- togl. inf. Posteriorly the end of the muscle on the ceratohyal is marked by the anterior edge of M. geniohy. In one specimen, M. ceratogl. lat. received a few fibers which came from the dermal end of M. dermogl. Origin. — There is fleshy origin from the ventro- and dorso-lateral sur- faces of the ceratohyal anterior to the most anterior part of the origin of M. geniohy. Insertion. — The dorsal and somewhat lateral surface of the anterior end of the basihyal and the postero-ventral and lateral corner of the entoglossum receive fleshy fibers. M. ceratoglossus inferior As may be observed in figure 10, M. ceratogl. inf. consists of three major divisions in Grus americana — lateral, medial, and posterior; the medial may in turn be composed of two parts. The medial and lateral divisions span the articulation between the ceratohyal and basihyal, and the inserting end of M. stylohy. crosses the ventral side of the lateral part. M. ceratogl. lat. is superior to both the medial and lateral parts of M. ceratogl. inf. in the anterior half of its length. The medial part (or parts) is approximately half the length of the latter fasciculus. The posterior slip of M. ceratogl. inf. was present in definable form in but one of the three specimens. It lies on the inner face of the ceratohyal bone, opposite M. ceratogl. lat. Origin. — The lateral part comes fleshily from the anterior 2 centimeters of the lateral surface of the ceratohyal, except that the most anterior 4 millimeters of this surface give fleshy origin for the medial part of the inferior division. The posterior division arises as fleshy fibers, adjacent and anterior to the origin of M. ceratogl. lat. from the medial surface of the ceratohyal. Insertion. — At the level of the posterior end of the basihyal the lateral 32 THE MYOLOGY OF THE WHOOPING CRANE part forms a tendon which passes anteriorly across the ventral aspect of the medial belly and the insertion of M. hypogl. obliq. Opposite the posterior end of the entoglossum the tendon is attached to and forms the origin of M. hypogl. rectus (fig. 10). The most anterior extent of the tendon, and the actual tendinous insertion, of the lateral part of M. cer- atogl. inf. is 0.5 centimeters anterior to the posterior end of the ento- glossum and on the ventro-lateral corner of this structure. This insertion thus lies at the anterior end of M. hypogl. rectus and is covered ventrally by M. geniogl. The insertion of the medial part is fleshy on the ventro-lateral edge of the middle third of the basihyal, deep to M. hypogl. obliq. and posterior to the insertion of M. dermogl. The posterior part inserts on the fascia overlying the joint between the urohyal and basihyal elements. M. hypoglossus rectus The Mm. hypogl. rectus and hypogl. obliq. would seem to be parts of the same sheet of muscle. However, as may be seen in figure 10, the fibers of the two lie nearly at right angles to each other. Both are covered ventrally by the medial part of M. geniogl. Origin. — Mudge (1903:247) noted that there was little variation in M. hypogl. rectus and gave its origin, for all forms (parrots) he dissected, as the postero-lateral process of the entoglossum. In the Whooping Crane the origin is consistently from both the postero-lateral process and the tendon of the lateral part of M. ceratogl. inf.; the latter part of the in- sertion is always the major part, only a few fibers coming from the de- scribed position on the entoglossum. Insertion. — From the lateral attachment the fibers go antero-mediad for a short distance and eventually fade into a strong, tendinous apo- neurosis which continues anteriorly on the ventral surface of the ento- glossum to the middle of the length of this structure. This aponeurosis is also the one on which the Mm. geniogl. meet in a superficial, midline raphe. M. hypoglossus obliquus As is shown in figure 10, the paired muscles of this name lie on the ventro-lateral surface of the anterior end of the basihyal and extend forward on to the posterior end of the entoglossum. Laterally they are deep to the tendon of the lateral part of M. ceratogl. inf. and to M. geniogl.; posteriorly they are medial and superficial to the one or two slips of the medial fasciculus of M. ceratogl. inf. Origin. — There is tendinous and fascial origin from the ventro-lateral corner of the posterior half of the length of the basihyal. Caudally this origin may be very attenuated. Insertion. — It is strongly fleshy on a longitudinal line on the posterior MUSCLES OF THE TONGUE REGION 33 end of the ridge forming the ventro-lateral corner of the entoglossum. This line is continuous with, but posterior to, the line of insertion of the tendon of the lateral part of M. ceratogl. inf. M. thyroglossus and M. thyrohyoideus These muscles extending from the posterior rim of the cricoid cartilage to the basihyal bone are considered together because in only one of three specimens was there any very obvious separation into a lateral M. thyrohy. and a medial M. thyrogl. The two names which include the "thyro" are retained here only through our desire to add no more confusion to the nomenclature of muscles; since there is no thyroid cartilage in birds, the use of the term is misleading. The paired masses (fig. 10) lie on the ventral surface of the larynx, separated from each other anteriorly by the urohyal bone. Posteriorly, in the mid-ventral line, only fascia separates the thyroglossal muscles of the two sides. If we regard the lateral part as M. thyrohy., we may then designate as M. thyrohy. access. (Mudge, 1903:232) the small slip which comes off the postero-lateral part. The posterior ends of M. thyrogl. and M. thyrohy. are superficially continuous with M. tracheolar. sup. and M. tracheohy. This continuity is, however, represented by only a few fibers and is but another indication of the fact that these four muscles represent the an- terior end of the more primitive sheet of muscle considered as M. ster- nohy. Origin. — The muscles originate from the ventral and lateral surfaces of the posterior end of the cricoid cartilage. There is, however, close fascial connection to the cricoid cartilage throughout the distance that the muscle traverses the cricoid. The part designated as M. thyrohy. access, arises primarily from the fascia of the floor of the mouth and pharynx just lateral to the glottis, but may get some fibers from the pos- tero-dorsal rim of the cricoid. Insertion. — The insertion of the fused mass is largely tendinous on the anterior end of the lateral surface of the basihyal, deep to the insertion of M. dermogl. The anterior part of the course of the muscle is covered by the medial and lateral parts of M. ceratogl. inf. M. tracheohy oideus The part of the primitive M. sternohy. lying posterior to the cricoid and on the lateral surface of the trachea forms this muscle (fig. 10). It is several times as large as M. tracheolar. sup. and extends posteriorly from the cricoid for about one-third the length of the neck (about 14 centi- meters in our specimens ) . A thin fasciculus comes from the dorso-medial corner of the anterior end and passes to the dorsal surface of the larynx (fig. 12). We found no convolutions or circumtracheal windings such as Steinbacher ( 1934, 1935 ) reported in some woodpeckers. Origin. — At its posterior end the muscle arises from the skin and from 34 THE MYOLOGY OF THE WHOOPING CRANE sternotrachealis tracheolaryngeus inferior syrinx Fig. 11. Lateral view of the left side of the posterior part of the trachea and the syrinx. the fascia between the trachea and the vertebral column. This dermal attachment is here considered the origin because primitively the pos- terior end of the muscle was connected to the sternum. Insertion. — The main body of the muscle inserts on the ventral, lateral, and dorsal surfaces of the posterior end of the cricoid (fig. 10). The small slip formed anteriorly crosses the surface of M. thyroaryt. on the dorsal side of the larynx and inserts fleshily on the dorso-lateral corner of the posterior end of the arytenoid cartilage (fig. 12). M. tracheolaryngeus superior Figure 10 shows the muscle on the ventral side of the trachea, immedi- ately lateral to the midline and separated from the same muscle of the opposite side by fascia only; in fact, the two almost seem to be continu- ous in the midline. M. tracheolar. sup. with M. tracheolar. inf. formerly constituted a continuous band from sternum to larynx. In birds the middle part of the length of this band has disappeared entirely or in part. This gives rise to considerable and frequent variations in length of the two parts. In one Whooping Crane (no. 2) M. tracheolar. sup. extended posteriorly 10 centimeters from the cricoid cartilage, and in another (no. 3) only 4 centimeters. Origin. — The ventro-lateral surfaces of three or four tracheal rings pro- vide fleshy origin. Insertion. — The medio-ventral edge of the posterior rim of the cricoid cartilage receives the fleshy anterior end of the muscle (fig. 10). MUSCLES OF THE TONGUE REGION 35 M. tracheolaryngeus inferior As was indicated above, there is considerable variation in the anterior extent of this muscle. In one specimen (no. 2) the anterior end of this muscle was 11 centimeters posterior to the cricoid cartilage and, except for a gap of 1 centimeter, formed a direct continuation of M. tracheolar. sup. In specimen number 3 the anterior end was 4 centimeters posterior to the cricoid but was on the dorso-lateral part of the trachea; thus in this specimen there seems to have been a dorsad movement away from the posterior end of M. tracheolar. sup. However, as it went toward the lower end of the trachea the muscle shortly assumed the usual mid-lateral po- sition. From this variable site anteriorly M. tracheolar. inf. continues caudally to the syrinx (fig. 11). (Because we did not wish to destroy the sternum, which is extensively penetrated by the trachea, the muscle could not be followed throughout its length. ) The muscle was present in the same relative position when the trachea entered and when it emerged from the sternum; it was, therefore, assumed to be continuous. Some increase in size is apparent in the muscle from the lower cervical region to the syrinx. Opposite the coracoid bone the longitudinal fibers of this muscle surround the insertion of M. sternotrach. Origin. — The mid-lateral or occasionally the dorso-lateral parts of the tracheal rings give fleshy origin. Insertion. — Two or three tracheal rings anterior to the syrinx the muscle forms a thin aponeurosis which fans out to attach to somewhat more than the middle half of the dorso-ventral length of the first syringeal ring (fig. 11). M. tracheolar. inf. does not give rise to any other syringeal muscles in the Whooping Crane; see Miskimen (1951:497-504) for a recent discussion of the relations of this muscle (her M. tracheo-lateralis ) to other muscles of the syrinx in passerine birds. M. sternotrachealis This is one of the few names that has been used consistently by avian anatomists. In addition to those workers listed on page 27, Mayr (1931: 337) and Miskimen (1951:497, 504) used the name M. sterno-trachealis. The entire muscle is only 6 centimeters long and but 5 or 6 millimeters wide (fig. 11). It arises from the most dorsal part of the dorsal or inner face of the sterno-coracoidal process of the sternum. It extends antero- dorsad to insert on the middle of the side of the tracheal rings opposite the coracoid, some 5 centimeters anterior to the syrinx. The insertion is fleshy and is surrounded, or nearly so, by the fibers of M. tracheolar. inf. The extrinsic syringeal muscles noted by Beddard (1898:368) as coming from the angle of the first rib must have been the Mm. sterno- tracheales. 36 THE MYOLOGY OF THE WHOOPING CRANE M. thyroarytenoideus This muscle is to be found on the dorsal side of the larynx (fig. 12). It virtually covers this surface, being separated from its counterpart of the opposite side by the glottis and parts of the arytenoid cartilage. M. constrictor glottidis is deep to this muscle. Posteriorly M. thyroaryt. is in contact, on the cricoid cartilage, with the dorsal part of the insertion of M. tracheohy. and is covered by the slip of this muscle that inserts on the posterior crest of the arytenoid cartilage. Origin. — In general the fibers can be said to arise fleshily from the posterior edge of the cricoid and from the posterior half of the length of the dorso-lateral edge of the lateral cricoid. Insertion. — The fibers pass antero-medially to insert fleshily on the lateral surface of the entire length of the arytenoid cartilage (fig. 12). M. constrictor glottidis The muscle is completely hidden from dorsal view by M. thyroaryt. (fig. 12) on the larynx and the most anterior extent of M. tracheohy. It lies on the dorsal surface of the cricoid cartilage and the lateral part of the arytenoid. Origin. — Fleshy origin is provided by the dorsal and lateral surfaces of the medial or middle cricoid cartilage. Insertion. — From this origin the fibers fan out anteriorly and some- what laterally. The primary insertion lies in the connective tissue anterior and lateral to the anterior apex of the arytenoid cartilage. Some fibers of the most lateral part of the belly may insert on the middle of the length of the dorso-medial rim of the lateral cricoid cartilage. arytenoid cart. pessulus tracheohyoideus Fig. 12. Dorsal view of the larynx and the musculature surrounding the glottis. Mm. tracheohy. and thyroaryt. have been removed on the left side. Muscles of the Orbit and the Ear M. orbicularis palpebrarum M. orbicularis palpebrarum— Shufeldt (1890:52-53) M. orbicularis — Gadow (1891:445) ?M. tensor periorbitae — Lakjer (1926:135) part M. constrictor palpebrae inferioris — Edgeworth (1935:275) M. levator palpebrae superioris M. levator palpebrae superioris — Shufeldt (1890:55-56) M. levator palpebrae — Gadow (1891:445) M. depressor palpebrae inferioris M. depressor palpebrae inferioris — Shufeldt (1890:56-57), Gadow (1891: 445), Lakjer (1926:135) part M. constrictor palpebrae inferioris — Edgeworth (1935:275) M. quadratus nictitantis M. quadratus nictitantis— Shufeldt (1890:57) M. quadratus membranae nictitantis — Gadow (1891:443) M. pyramidalis nictitantis M. pyramidalis nictitantis— Shufeldt (1890:57-58) M. pyramidalis membranae nictitantis — Gadow (1891:443-444) M. obliquus superior all in common use in vertebrates: Shufeldt (1890:58-61), Gadow (1891: 442-443) M. obliquus inferior M. rectus superior M. rectus inferior M. rectus externus M. rectus internus M. tensor tympani— Shufeldt (1890:62-63 Gadow (1891:462) No variations from the usual pattern in birds were found in any of the eye muscles. In figure 2 the origins are indicated, and figure 13 shows the insertions. The only attachments not shown are: the maxillo- jugal part of the origin of M. orbic. palp., which was removed with the skin, as was the insertion of this muscle on the lower eyelid; the insertion of M. lev. palp, on the upper eyelid, removed with skin; the insertion of sup. rect ext. rect tendon of pyramid, nict. optic nerve inf. rect sup. obliq. quadratus nictitantis int. rect. pyramidalis nictitantis inf. obliq. Fig. 13. The muscles of the eyeball as seen from the medial side of the eye. Only Mm. pyramidalis nict. and quadratus nict. are completely shown; all other muscles have been cut near their insertions. 38 THE MYOLOGY OF THE WHOOPING CRANE M. depress, palp., removed with lower lid; and the insertion of M. pyra- midalis nict. on the nictitating membrane. M. tensor tympani, if present in the ear region, was destroyed in skin- ning. Muscles of the Wing Most of the names of the muscles of the wing follow Fisher ( 1946:607- 611), who has compared his nomenclature with that of earlier workers. However, Montagna ( 1945 ) demonstrated that the digits of the avian hand are numbers II, III, and IV rather than I, II, and III as in most cur- rent literature. Thus is settled, at least to our satisfaction, the hundred- year-old controversy. Names of certain of the wing muscles must be changed to avoid confusion. Below, the old names are given in brackets following the new names. The new names were chosen after consultation with a number of anatomists. We here list, in the sequence in text, the names used; this should facilitate use, as in general the muscles are treated in the sequence of removal from the specimen. M. tensor patagii longus M. tensor patagii brevis M. pectoralis M. supracoracoideus M. sternocoracoideus M. coracobrachialis posterior M. latissimus dorsi M. cucullaris, hals part M. rhomboideus superficialis M. rhomboideus profundus M. coracobrachialis anterior M. deltoideus minor M. proscapulohumeralis and M. subscapularis M. proscapulohumeralis brevis M. dorsalis scapulae M. serratus posterior M. serratus profundus M. serratus anterior M. subcoracoideus M. biceps M. deltoideus major M. triceps M. brachialis M. extensor metacarpi radialis M. extensor digitorum communis M. supinator brevis M. flexor metacarpi radialis M. pronator brevis M. pronator longus M. extensor longus digiti II [extensor pollicis longus] M. anconeus M. extensor longus digiti III [extensor indicis longus] flexor digitorum profundus flexor carpi ulnaris flexor carpi ulnaris brevis abductor alae digiti II [abductor pollicis] adductor alae digiti II [adductor pollicis] flexor digiti IV [flexor digiti III] flexor brevis digiti IV [flexor brevis digiti III] M. abductor minor digiti III [abductor digiti II] flexor metacarpi brevis interosseus dorsalis interosseus ventralis extensor brevis digiti II [extensor pollicis brevis] abductor major digiti III [abductor indicis] flexor digiti II [flexor pollicis] flexor metacarpi posterior M. M. M. M. M. M. M M. tensor patagii longus The complex topographical relationships of this muscle may be ob- served in figures 16 and 18. The intricate mechanism has three major sources of origin (figs. 16, 18 and described below) from the shoulder 39 40 THE MYOLOGY OF THE WHOOPING CRANE O MUSCLES OF THE WING 41 u Q 03 42 THE MYOLOGY OF THE WHOOPING CRANE region. Halfway out the humeral length these three parts form a wide elastic tendon (fig. 16) which almost immediately subdivides. Both the latter subdivisions send inelastic tendons to the region of the elbow. The subdivided elastic tendons are 10 centimeters long, and they fuse distally to form an inelastic tendon which courses to the wrist in the anterior edge of the patagium, passes through the tendinal groove in the antero-distal surface of the radius, and goes to the metacarpus. Such complexity in the tendinous arrangement is apparently not present in Balearica pavonina ( Mitchell, 1901 ) . Our specimens of americana do not agree with the statements of Lowe ( 1931a, 1931b ) that the tensor tendons are simple and represent an "archaic" condition. In G. canadensis we found no com- plicated system of slips to the wrist. The ventral division of N. brachialis longus sends a twig to this muscle from the branch serving M. biceps (fig. 14). Origin. — The most anterior source is by a non-elastic tendon from the anterior edge of the tendon of M. tens. pat. brevis at the junction of this latter tendon with its belly. The middle origin is a strong elastic tendon arising from the distal end of the anterior surface of the deltoid crest of the humerus and at approximately the middle of the length of M. delt. major. The only muscular origin is the posterior one (figs. 16, 17, 18) which comes from the antero-palmar surface of M. biceps at the level of the middle of the deltoid crest. Beddard ( 1898 ) described a similar, but tendinous, origin in Anthropoides virgo, and Gadow (1891:255) listed this bicipital muscular origin as typical of Grus. We found it in G. cana- densis. Its tendinous origin is in common with that of M. biceps and deep to the fleshy superficial part of M. pect. The anterior and middle sources of origin unite to form an inelastic tendon which shortly joins the tendon of the posterior and muscular origin. Insertion. — The major and usual insertion is on the most antero-proxi- mal part of the extensor process of metacarpal II, palmar to the insertion of M. extens. longus dig. II (figs. 16, 18, 20, 21). The six inelastic tendons extending posteriorly from the wide elastic tendon in the middle of the patagium attach to the broad fascial covering of the anconal aspect of the elbow and forearm. The presence of elastic tendon in the origin and in the middle of the length of the primary tendon of insertion suggests that there may perhaps be little muscular action involved in the functioning of this muscle. When the forearm is extended, the elastic tendons in the inserting tendon and in the origin would hold the patagium taut. With the wing partly or com- pletely flexed, the small muscular belly of the origin might aid in tighten- ing the patagium. In line with the view that a muscle can contract to one-third or one-half the length of the relaxed belly, it is difficult to see how this muscle, which is so short in relation to the length of the insert- ing tendon, could do much effective work when the forearm is even partly MUSCLES OF THE WING 43 flexed. Flexion of the hand would automatically tense the entire complex of this muscle. M. tensor patagii brevis The elongately triangular belly lies on the antero-dorsal aspect of the shoulder (figs. 16, 18, 22, 25) just anterior to M. delt. major, dorsal to the proximal part of M. pect., and anconal to the middle and posterior origins of M. tens. pat. longus. The belly is one-fourth the humeral length; at the level of formation of this tendon there are wide aponeurotic attach- ments to the deltoid crest of the humerus. The muscular origin of M. tens, pat. longus also arises here. A branch of the 16th spinal nerve (fig. 14) passes across the dorsal proximal surfaces of Mm. delt. major and minor and penetrates the deep side of the proximal part of the belly. In one bird, and only on the right side, a second innervation was present; it came from the superior division of the plexus. Origin. — The origin is mixed fleshy and tendinous from the lateral face of the most dorsal part of the furculum. There is wide fascial connection proximally to the surface of M. cucullaris, hals pt., and antero-ventrally to the surface of M. pect. Insertion. — The origin of part of M. tens. pat. longus should be con- sidered one insertion of M. tens. pat. brevis, for, with the forearm ex- tended, contraction of the latter muscle would tense M. tens. pat. longus. Lowe ( 1931b ) listed as one feature of the Gruidae the absence of any "wristward slip." To us this slip to M. tens. pat. longus constitutes a "wristward slip"; we also found this in the Little Brown Crane. The prin- cipal insertion is, however, by a wide, flat tendon which passes down the antero-anconal edge of the upper wing musculature and moves out some- what distally in the patagium to insert widely on the strong fascia over the elbow (fig. 18). Within this fascial attachment is a particularly strong band of fascia that inserts on the tendon of origin of M. extens. meta. rad., pars anconalis. This connection to the origin of M. extens. meta. rad. in effect serves M. tens. pat. brevis as an insertion on the ecte- picondyle of the humerus. Perhaps this posterior band of fascia in the attachment is comparable to the "inner division" of Lowe, who found this division absent in Balearica but present in chicks of Grus grus. In G. canadensis the wide tendon continues posteriorly over the surface of the wing to insert on the tendon of origin of the wide anterior and super- ficial part of M. flex, carpi ulnaris. It is of interest that M. tens. pat. brevis in one specimen ( fig. 16 ) has a divided tendon of insertion; in the other birds the tendon is single (fig. 18). M. pectoralis This, the largest muscle of the body, is easily separated into superficial and deep portions. These are so distinct they will be considered sepa- 44 THE MYOLOGY OF THE WHOOPING CRANE > MUSCLES OF THE WING 45 rately. Beddard (1898:366) found this double layer in Bugeranus carun- cirfatus and Balearica pavonina. In Grus canadensis we found the two parts to be hardly separable; the deep part is weakly developed. Inner- vation is from branches of the inferior trunk of N. brachialis longus (figs. 14, 15). Superficial part. — The position and relationships are well shown in figures 16 and 25. There it may be seen that on the ventral side of the body this muscle is superficial to the origins of Mm. biceps, triceps, and tens. pat. longus; in figures 17 and 29 the relations with the deep layer and with M. supracoracoid. may be observed. Origin. — It is entirely fleshy from that part of the sternal plate not used by M. supracoracoid., except that there is a small posterior part not utilized by either muscle. A major part of the fleshy origin is from the lateral surface of the keel and the furculum as far antero-dorsally as the coracoid. At the postero-dorsal edge of the belly the origin extends dor- sally on to M. ext. obliq. Insertion. — Although there are some tendinous fibers, the insertion is primarily fleshy on the palmar side of the deltoid crest of the humerus. The distal part of the insertion is on a rounded papilla at the distal end of the deltoid crest, by a wide, thick tendon which extends to the area of insertion by passing beneath and through the fleshy insertion on the deltoid crest. We found the insertion in canadensis to be fleshy except for an underlying sheet of connective tissue extending from origin to in- sertion; the poorly developed deep part of the muscle inserts on this sheet. Deep part. — There was considerable variation in the conformation of this layer. The left side of the bird whose right side is depicted in figure 17 showed a more "normal" or usual situation. The fibers were nearly at right angles to the axis of the tendon of origin of Mm. biceps and tens, pat. longus, and not parallel to it as shown in figure 17. On the left side the blood vessels and nerves perforated the posterior edge of this deep part, as they usually do, and they did not lie outside as shown in the drawing. Origin. — In one-half of the dissections origin is from the most ventral part of the tracheal enclosure at the anterior end of the sternum and from fascia lying between this enclosure and the furculum. There is also some fibrous and fascial origin from the surface of M. supracoracoid. In the instance figured the origin was from the surface of the anterior half of M. supracoracoid. with only slight origin from the tracheal en- closure; this condition of the origin is to be found in the remainder of the dissections. Insertion. — In no specimen did this deep part insert on anything other than the tendon of origin of Mm. biceps and tens. pat. longus. There is no attachment to the tubercle on the deltoid crest of the humerus, where 46 THE MYOLOGY OF THE WHOOPING CRANE this part of the pectoralis complex frequently inserts. As has been de- scribed, there is tendinous insertion on this papilla, but it comes from an inseparable part of the superficial layer. Insertion on the originating tendon of M. biceps, rather than directly on a more distal part of the humerus itself, would seem to decrease the effectiveness of action, and the only possible function when the arrangement is as shown in figure 17 is a bracing of the coracoid. coracoid deltoid crest biceps furculum heavy fascia supracoracoideus Fig. 17. Ventrolateral view of the deep breast muscles to show variation in direction of fibers of the deep part of M. pect. and its unusual insertion. M. supracoracoideus This is the deepest of the pectoral muscles ( figs. 17, 29 ) and is of pin- nate structure. The anterior half of the fleshy belly is immediately beneath the deep part of M. pect. but is separated from it by a heavy aponeurotic sheet extending from the furculum to the coracoid, and the posterior half is deep to the superficial part of M. pect. Just posterior to the sterno- coracoidal articulation, nerves and blood vessels enter the middle of the length of the dorsal edge of the belly after emerging from a foramen in the coracoid. The nerves are branches of the trunk of N. brachialis longus, but they come off proximal to the area of formation of the in- ferior and superior trunks. Thus it can only be noted that the fibers may come from either the 15th or 16th spinal nerves or from both. Although the superficial pinnate structure of the muscle is as shown in figure 29, this pinnate part constitutes less than one-third of the bulk of the muscle. The deeper two-thirds consist of fibers which form a ten- don along the dorsal edge of the belly. The two tendons fuse opposite approximately the middle of the coracoidal length. There is a fleshy anterior part of the muscle which is identical to that MUSCLES OF THE WING 47 described for cathartids by Fisher (1946:579), except that it continues dorsad up through the triosseal canal and inserts on the tendon of the main part of the M. supracoracoid., beneath the belly of M. delt. minor (fig. 19). Origin. — Fleshy origin comes from all the surfaces of the keel and the sternal plate covered by the belly ( fig. 29 ) . This extends anteriorly on to the proximal half of the anterior face of the coracoid and to the most anterior extent of the bony tracheal enclosure formed by the sternum. The anterior fleshy part arises from the medial edge of the coracoid, the lateral surface of the furculum, and the fascial sheet between the cora- coid and the furculum. Insertion. — A strong tendon emerges from the dorsal end of the trios- seal canal, passes distally beneath M. delt. minor, and attaches to the an- conal surface of the external tuberosity of the humerus. M. sternocoracoideus The tripartite belly of this muscle lies anterior and superficial to the sternal part of the second rib, deep to the anterior edge of M. ext. obliq., and superficial to the outer layer of the intercostal muscles (fig. 29). There is always innervation from the same inferior trunk of N. brachialis longus that goes to the great pectoral muscles ( figs. 14, 15 ) ; there may be a second nerve from the fused trunk formed by nerves 15 and 16. Origin. — The dorsal fasciculus arises as mixed fleshy and tendinous fibers from the antero-lateral surfaces of the second rib, and the more ventral band comes from the posterior edge of the second sternal rib and the antero-lateral surfaces of the third sternal rib. The anterior bundle arises fleshily from the entire length of the sternocoracoidal process of the sternum, deep to the belly of M. coracobrach. post. Insertion. — There are also three parts to the insertion. The more pos- terior and superficial insertion is mixed fleshy and tendinous on the pos- terior edge of the sternocoracoidal process of the coracoid. The deeper insertion here is tendinous on the most dorsal aspect of the sternocora- coidal process of the sternum. The most anterior bundle of the belly in- serts by means of fleshy and tendinous fibers in the usual sternocoracoidal impression on the coracoid. M. coracobrachialis posterior The heavy, fleshy belly is bipinnate and lies on the proximo-lateral surface of the coracoid, but as it extends dorsally it curves around to lie on the posterior surface of the shaft of the coracoid. The antero-lateral part of the belly is in contact with M. supracoracoid. and the middle and proximal parts of the belly cover most of the distal parts of M. sterno- coracoid. (fig. 29). Blood vessels and nerves emerging from the chest cavity send branches to the superficial surface of the dorsal part of the belly. Innervation is by a branch from the fused 15th and 16th spinal 48 THE MYOLOGY OF THE WHOOPING CRANE nerves prior to the separation into superior and inferior divisions (fig. 14), and sometimes from the inferior division. Origin. — The origin is fleshy from the lateral half of the anterolateral face of the proximal one-half of the coracoidal length and extends me- dially and dorsally on to the postero-lateral aspect of the coracoid. In the middle of the coracoidal length the free belly is separated from the bone by a large vein which comes proximally around the head of the humerus. Insertion. — The tendon inserts on the internal tuberosity of the hu- merus. M. latissimus dorsi This muscle usually consists of three parts lying on the superficial as- pect of the interscapular region and extending from the vertebral column to the humerus (figs. 18, 22, 25). The posterior band is deep to the anterior bundle, where they cross, and the dermal component, if present, may be superficial to the posterior band or may be a caudal division of this band. These two conditions of the dermal fasciculus are shown in figures 18 and 22; the left side of the bird whose right side is shown in figure 18 did not have any dermal muscle in this region. The variation in size of this dermal part may be seen by comparing figures 18 and 22. Gadow (1891:228) found no pars metapatagialis in G. leucogeranus. Our specimen of the Little Brown Crane showed the condition illustrated on the right side of figure 22. The innervation is complex. The most dorsal part of the anterior belly often receives branches of the 19th and 20th posterior primary rami which come out through the fleshy sheet of M. rhomb, superf. The 21st posterior primary ramus sends twigs to the posterior part of M. lat. dorsi and to the dermal component (fig. 14). In this same figure and in figure 15 it may be observed that various twigs of the superior division of N. brachi- alis longus serve this muscle complex. Origin. — The anterior part arises by a thin aponeurosis 7 centimeters wide from the neural crests of the thoracic vertebrae. This origin (figs. 18, 22) is just superficial to the origin of M. rhomb, superf. Another apo- neurosis, starting approximately 1 centimeter posterior to the anterior one and going caudad to the fascial origin of M. extens. ilio-tib. ant., forms the origin for the posterior band of M. lat. dorsi. There may also be fascial origin from the connective tissue overlying the costal musculature. In some instances the origin of the posterior band is deep to the origin of the dermal part, but this seems to be less frequent in occurrence than is the formation of the dermal component as a fasciculus of the posterior band. The posterior edge of M. lat. dorsi, post, pt., just covers the caudal end of the scapula. Insertion. — The anterior part inserts fleshily on a narrow line, some 5 centimeters long, beginning about four centimeters from the proximal end of the humerus. The belly enters the musculature of the upper arm MUSCLES OF THE WING 49 palmar to the scapular head of M. triceps and anconal to the entrance of M. lat. dorsi, post. pt. The tendon of this latter part of the muscle attaches to the deep side of the anterior part but also inserts on the humerus beneath the fleshy insertion of the anterior portion. M. cucullaris, hals part This band of muscle, some 9 centimeters wide, lies over the anterior part of the cervico-thoracic region (figs. 18, 22, 25) and extends to the shoulder. Posteriorly the muscle is in contact with M. rhomb, superf. and distally with Mm. pect, tens. pat. brevis, and delt. major. The posterior part of the muscular sheet overlies the anterior edge of M. rhomb, prof. Anteriorly on the neck the muscular fibers are smaller and more widely spaced. Branches from the combined 14th and 15th spinal nerves and posterior primary ramus 15 go to this muscle (figs. 14, 15). In some in- stances, nerves to this muscle may come from the 14th and 15th prior to the fusion of the nerves. Origin. — A thin aponeurosis from the most dorsal part of the neural crests of vertebrae 18, 17, 16, and the posterior part of 15 provides the origin for the muscle (figs. 18, 22). Insertion. — The posterior part of the muscle, consisting of shorter fibers, inserts fleshily and tendinously on the most anterior centimeter of the dorso-medial edge of the scapular head and is perforated by blood vessels and nerves emerging from the triosseal canal. The insertion an- teriorly and ventrally continues to be largely fleshy, but with some ob- vious fascial connections, on the antero-medial edge of the furculum. Attachment to the furculum continues ventrad to within 4 centimeters of the furcular symphysis. It is of interest that the ventral portion of the hals part of M. cucullaris, between the clavicle and the trachea, is very closely adherent to the un- derlying clavicular air sac. There is wide aponeurotic origin from the fascia overlying the lateral surface of the base of the neck. The short muscular fibers originating here are only one-third the length of those in the main belly. It would seem, therefore, that the sparse and thin belly dorso-anteriorly and the complete absence of the dorsal two-thirds of the existing antero-ventral fibers indicate a considerable reduction in the anterior extent of this muscle. M. rhomboideus superficialis The short but wide belly of this muscle lies between the scapula and the vertebral column, deep to M. lat. dorsi, and at its anterior edge super- ficial to M. rhomb, prof. (figs. 18, 22). The fibers fan out somewhat, as they pass laterally. The innervation is through the posterior primary rami of spinal nerves 19 and 20 ( fig. 14 ) . Origin. — An aponeurosis from the neural crests of all vertebrae from 50 THE MYOLOGY OF THE WHOOPING CRANE .2. -I PT = E o o *- \ o- CL o . o o °--S. ^E ° o. . x a> c