502 



Vertebrata, 



Herbivorous animals^ generally of considerable size, with plicate or 

 tuberculate molars, and usually with a long csecum. 



Sub-Order 1. Perissodactyla. 



The third digit is almost symmetrical, stronger than the 

 rest, and the median plane of the foot passes through the middle of 

 it ; the fifth is usually absent. The femur has on its outer edge a 

 process {trochanter tertius), which is wanting in the Artiodactyles. 

 On the distal surface of the astragalus there is a large, flat, articular 

 facet for the naviculare, and a smaller one for the cuboid. The 

 rami of the lower jaw are anchylosed. The molars are folded, and, 

 with the exception of the first premolar, of about equal size. 

 Stomach simple ; csecum colossal ; placenta diffuse.* 



1. The Tapir (Tapirus). Tore foot -witli four toes (all but the poUex), hind 

 foot with three (hallux and minimus wanting) ; the third is not much stronger 



Fig. 404. Hand (fore foot) of : A Tapir, B Ehinooeros, C Horse. B radius, u ulna 

 s, I, c proximal row of oarpals (na-viculare, lunare, cuneiform) ; p pisiform ; tm, td, m, u 

 distal row of oarpals (trapezium, trapezoid, os magnum, unciform) ; II — V second — fifth 

 fingers (in B, Y is the rudimentary fifth metacarpal, in 0, II and 17 denote the second and 

 fourth metacarpals). — After Flower. 



than the second and foui-th; digitigrade. -i f, c i, y f, m f ; the molars have 

 each two transverse ridges; the snout is elongated to fonn a short proboscis; 

 the skin is well covered with hair. One species in the East Indies, another in 

 South America. The extinct (Eocene) genus, Palxotherium, is somewhat closely 



* Gall-bladder absent, 

 vertebrse. 



Two abdominal mammse. At least twenty-two dorsal 



