2 CATALOGUE OF UNGULATES 



Its existing representatives are divisible into four sub- 

 ordinal groups, of which the names and leading distinctive 

 features are as follows : — 



A. The bones of the upper and lower transverse rows 



of the wrist-joint, or carpus, alternating with 



one another, so as to permit the os magnum to 



articulate with the scaphoid (instead of the 



lunar or cuneiform) ; toes never more than 4 in 



number. 



a. The two middle toes (which may be the 

 ouly ones), or those representing the 3rd 

 and 4th of the 5-toed foot, equal in size 

 and symmetrical to a vertical line drawn 

 between them. Distribution co-exten- 

 sive with that of the whole order Aetiodactyla. 



6. The third toe (which may be the only 

 one) larger than the lateral ones (when 

 present), and symmetrical in itself. 

 Eestricted at the present day in a wild 

 state to the Old World Peeissodactyla. 



Pig. 1. — Bones of the Eight Poee-Peet or the 

 Pig (A), the Deeb (B), and the Camel (C). 



R, radius ; If, ulna, below which come the two rows of small 

 bones constituting the carpus, or wrist ; c, cuneiform ; I, 

 lunar ; s, scaphoid ; xi, unciform ; m, magnum ; td, trapezoid. 



The Roman numerals indicate the toes. 



From Flower's Osteology of the Mammalia. 



