108 COMPARATIVE OSTEOLOGY. 



the posterior foramen is inconstant, usually opening on the posterior edge. 

 The axis is broad anteriorly, with a small odontoid process, and extended 

 articular surfaces ; small transverse processes are pierced by large vertebral 

 foramina ; the neural spine is tall and thin. The five posterior segments have 

 large neural spines, the prominens especially so. 



There are usually 14 dorsal vertebrae, with short centra, increasing in length 

 from before backwards. The neural spines are broad, decreasing gradually 

 from the first backwards ; the first is nearly upright, the rest slope backwards, 

 excepting the last two or three, which are slightly inclined forwards. Two 

 foramina enter the neural canal on each side from the base of the transverse 

 process. The lumbar vertebrae number 6, sometimes 7 ; their centra are 

 longer than in any other region, resembling those of the ruminant. The 

 neural spines are strong-pointed, and bifid at the posterior borders, the 

 diverging laminae being continuous with the posterior oblique processes ; the 

 transverse processes are long, nearly horizontal, and without articular surfaces ; 

 the base of each is pierced by a small foramen leading into the neural canal. 

 The sacrum is usually made up of 4 segments ; the neural spines are very 

 rudimentary, in fact the laminae scarcely coalesce, leaving the neural canal 

 partly open ; the articular processes are large and overlap those of the last 

 lumbar vertebra. The coccygeal bones vary in number, being usually from 18 

 to 23, and the anterior ones have articular processes. 



Generally there are 14 pairs of ribs 7 true and 7 false. They are thin and 

 flat, the last three having their tubercles and the posterior part of their heads 

 united. The second, third, fourth, and fifth have true articulations distally. 

 The sternum is very long, and consists usually of 7 segments, the manubrium 

 remaining separate as in the ox. The cariniform cartilage forms a long 

 eminence terminating in a blunt point. 



APPENDICULAR SKELETON. 

 PECTORAL LIMB. 



The scapula is large, without an acromion process ; it has a prominent 

 spine, bearing in its centre a large tubercle, which inclines backwards over 

 the postea-spinatus fossa. The humerus is short, and compressed laterally, the 

 head inclining backwards ; the bicipital groove is single, and the external 

 trochanter is very large, with its summit curved over the bicipital groove, as 

 in the ox ; the external tuberosity is small, the internal one being replaced 

 by muscular imprints. The radius is small, and much curved ; while the ulna 

 is a true long bone, having a medullary canal, and extending to the carpus, 

 with which it articulates. The radius and ulna are united by. ligaments, 

 which rarely become ossified. The ulna is flattened from side to side, and lies 

 on the posterior face of the radius, in close connection, except that there exists 

 a radio-ulnar arch. The olecranon is prominent. The carpus consists of 8 

 bones, 4 in the upper and 4 in the lower row. The bones of the upper row 

 are similar to those of the horse, the cuneiform articulating above with the 

 ulna and a small portion of the radius, the lunar and scaphoid bones with the 

 radius, but the trapezium with neither of the bones of the forearm. The 

 bones of the lower row decrease from without inwards, and are the unciform, 

 articulating with the two external, the os magnum with the large internal, and 

 the trapezoid with the small internal metacarpal bones ; the pisiform, ter- 



