312 MAMMALIA. 



Cuvier were established ; these are the Perissodactyla (Pachy- 

 dermes a doigts impaires Cuv., and Solidungula Aut.) with an odd 

 number of toes, and the Artiodactyla with an even nnmber of toes. 

 The names do not correspond strictly with the number of the toes 

 since there are Perissodactyles as the Tapir and Eohippus which 

 have four toes on the front feet ; and on the other hand, there 

 are Artiodactyles as Anoplotherium tridactyle, which have three 

 toes on both front and hind feet. But, when applied in a limited 

 v sense with reference to the number of the pillar-like support- 

 ing bones of the middle digit or digits, the names are in all cases 

 suitable. In the Perissodactyla the unpaired central digit serves as 

 the principal support, which in the Artiodactyla is afforded by the 

 third and fourth digits which are symmetrical and similar. In most 

 Perissodactyla there are three digits of which the middle one is 

 specially strongly developed. The forms which exist at the present 

 time are confined to the families of the Tapiridce, the Rhinoceridce> 

 and the Equidce, of which the last were represented as far back as 

 the eocene epoch (Anchitherium) by forms which constitute con- 

 necting links between the Paloeotheridce and Tapiridce on the one 

 hand, and the ancestral forms of living horses on the other. 



Fam. Tapiridae. Short-haired Ungulates of medium size, with movable,. 



3'3 1*1 4*4 3'3 



proboscis. Dentition : i. c. p.m. m. . The moderately -long 

 3*3 11 3*3 3*3 



front legs end with four (fig. 670 <?.), the hind legs with three digits. Tapiru* 

 indicus Desm., East India ; T. americanus L., South America. 

 Fam. Rhinoceridas. Large unwieldy Pachyderms with one or two epidermal 



horns on the strongly-arched nasal bones. Dentition : i. c. - p. m. - 



1*1 O'O 4*4 



3*8 



m> Q~Z* ^ ae f ur incisor teeth are rudimentary, and sometimes fall out in old. 

 o.m 



age. Rhinoceroses appeared in the miocene, and are also found in the pliocene 

 and diluvium of Europe. Rhinoceros javanus Cuv., Java ; Rh. sumatrensis 

 Cuv.; Rh. africanus Camp.; Rh. t ichor hinus Cuv., with bony nasal septum, and 

 hairy skin ; diluvial, found well-preserved in ice. Rh. leptorhinus Cuv., upper 

 tertiaries, in Italy and south of France. 



Fam. Equidae (Solidungula Aut.). Long-limbed, slender Ungulates of con- 

 siderable size. The three-jointed middle digit alone treads upon the ground,, 

 and its strong terminal joint surrounded by a broad hoof (fig. 690). The 

 second and fourth digits are either present as small accessory digits (in fossil 

 horses), or are reduced to the metatarsal (metacarpal) bones (splint bones). 



The dentition (fig. 691) consists of six upper and six lower, large chisel- 

 shaped incisors, which are arranged in a curved line, and are distinguished by 

 the transversely oval pit on their biting surfaces. Canine teeth are as a rule 

 present only in the male sex in both jaws, and are small and conical. 



In the fossil forms there are seven grinders on each side in each jaw ; in the 



