MAMAIALIA. 575 
present, the hoofs are not compressed and there is no fusion of the 
metapodials. In Pliocene and Pleistocene times the Auppopolamide 
were found throughout Eurasia. 
Family II.—Suide.—The pigs have « bunodont dentition with 
many tubercles which, when worn, form irregular crowns. The canines 
grow from persistent pulps and form tusks. The dental formula is 
Fig. 390.—THE AFRICAN WATER-CHEVROTAIN 
(Dorcatheritim aguaticun). 
(From FLower and LyDDEKER.) 
” typical $144. The stomach is simple and the diet omnivorous. All 
four toes are present, but the second and fifth are shortened up and the 
hoofs of the third and fourth are compressed into the middle line, forming 
the ‘‘cloven hoof.” The metapodials and tarsal bones are, however, not 
yet fused and the ulna and fibula are still unreduced. The placenta 
is diffuse. The typical pigs are confined to the old world, but the 
peccaries (Dicotyles) are found in South America; they differ in 
dentition from the true pigs. 
“ Family I1I.—Tragulide.—This is a small family of little Ungulata 
called the chevrotains. In dentition they most nearly resemble the Pecora 
