CHARACTERS OF EVEN-TOED HOOFED BEASTS. 173 



especially at the forepart; a small and delicate head is 

 supported on an unusuallj long neck. The number of 

 vertebrae here, however, accords with that characteristic 

 of the mammalian class, viz: seven. They are peculiar 

 for the length of their bodies. There are fourteen dorsal 

 vertebrae with very long spinous processes, and support- 

 ing long and slender ribs, especially the anterior ones, 

 seven pairs of which join the sternum, which consists of 

 six bones ; the lumbar vertebrae are five in number, the 

 sacral four, and the caudal twenty; this series is termi- 

 nated in the living animal by a tuft of long, wavy, stiff 

 black hair, forming an admirable whisk to drive off insect 

 tormentors. The bladebone, 51, is remarkably long and 

 slender ; its spine or ridge forms a very low angle, and 

 gradually subsides as it approaches the neck of the sca- 

 pula; the coalesced coracoid is a large tuberosity. The 

 humerus, 53, forms the shortest of the three segments of 

 the limb ; it is remarkable for the strength of the proximal 

 processes ; the second segment is chiefly constituted, as in 

 all ruminants, by the radius, 55 ; the slender shaft of the 

 ulna, 56, which supports a long olecranon, becomes blended 

 with the radius, and lost at its lower third, but its distal 

 end reappears as a distinct part. The metacarpals of the 

 retained digits, answering to the third and fourth in the 

 human and other five-fingered (pentadactyle) hands, are 

 blended together to form a single " cannon-bone" of the 

 veterinarians ; but the nature of this is different from that 

 in the horse ; it divides at its distal end into two well- 

 formed trochlea), or pulley -joints, and to these are articu- 

 lated the digits Hi and w, which each consist of three joints 

 or phalanges. Thus the main extent of this singularly 

 elongated limb is gained by the excessive development of 

 the hand-segment, restricted, however, to those elements 



15- 



