700 



MAMMALIA. 



third trochanter or process for the insertion of muscles. 

 There are usually twenty-three dorso-lumbar vertebras. 



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 ceecum is large, there is no 

 gall bladder. 



The mammae are inguinal ; the placenta is diffuse and 

 non-deciduate. 



Faviilies of Perissodactyla. 



Family Tapiridoe. In the Tapirs ( Tapirus), there are four digits in 

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



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

 teeth exposed. (From Edinburgh Museum of Science 

 and Art.) 



P, Parietal ; F, frontal ; «, nasal ; /w, premaxilla; }i!, maxilla; 

 j\ jugal ; /, lachrymal ; sg, squamosal ; //, paroccipital process; c, 

 canine ; C, condyle. 



fifth digit scarcely reaches the ground, 

 digits. The dentition of the genus 



The hind foot has three 



3143 

 s ■ The orbit and 



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. Tlie genus was once 

 widespread, it has survived in these two widel)- separated 

 regions. 

 Family Equid;e. In the modern horses (Etjinis). there is on e.ich 

 foot one functional digit — the third, with splints representing the 

 metacarpals and metatarsals of the second and fourth. Professor 



