700 MAMMALIA. 



third trochanter or process for the insertion of muscles. 

 There are usually twenty-three dorso-lumbar vertebrae. 



As to the dentition, the premolars and molars form a 

 continuous series, with broad transversely ridged crowns, 

 the last premolars often very like the molars. 



The stomach is simple, the caecum is large, there is no 

 gall bladder. 



The mammae are inguinal ; the placenta is diffuse and 

 non-deciduate. 



Families of Perissodactyla. 



Family Tapirid^e. In the Tapirs ( Tapirus\ there are four digits in 

 the manus, but the third finger is still practically median, as the 



F P 



\ 



pp - 



FIG. 256. Side view of Horse's skull, roots of back 

 teeth exposed. (From Edinburgh Museum of Science 

 and Art.) 



P, Parietal ; F, frontal ; n, nasal ; pm, premaxilla ; m, maxilla ; 

 j, jugal ; /, lachrymal ; s<?, squamosal ; //, paroccipital process ; c, 

 canine ; C, condyle. 



fifth digit scarcely reaches the ground. The hind foot has three 



3 T 43 



digits. The dentition of the genus is The orbit and 



3133 



temporal fossa are continuous. The nose and upper lip form a 

 short proboscis. The thick skin has but scanty hair. In habit, 

 the Tapirs are shy and nocturnal, fond of forests and water, 

 feeding on tender shoots and leaves. The distribution is some- 

 what remarkable, for four species live in Central and South 

 America, while a fifth is Malayan. The genus was once 

 widespread, it has survived in these two widely separated 

 regions. 



Family Equidae. In the modern horses (Eqnus), there is on each 

 foot one functional digit the third, with splints representing the 

 metacarpals and metatarsals of the second and fourth. Professor 



