HOOFED MAMMALS 



847 



Order Ungulata 



Hoofed Animals — Artiodactyla, Perissodactyla, Hyra- 

 coidea, Proboscidea, and extinct sub-orders. 



This large and somewhat heterogeneous order includes 

 pigs, hippopotamus, camels, cattle, deer, tapirs, rhino- 

 ceros, horses, hyrax, elephants, and some other distinct 

 types. 



They are terrestrial, and for the most part herbivorous 

 Mammals. Their digits generally end in hoofs or at least in 

 broad flat nails. In the adults of the modern types there 

 are no clavicles. The teeth are diverse, the milk set in 

 part persistent until the animal attains maturity. 



Ungulata Vera : Artiodactyla and Perissodactyla 



Artiodactyla — Pigs, Camels, 

 Chevrotains, and Ruminants. 



The third and fourth digits of each 

 foot are equally developed, and 

 the line halving the foot runs 

 between them. 



The premolars and molars are 

 usually different, but generally 

 bunodont or selenodont. 



There are nineteen dorso -lumbar 

 vertebrae. 



The femur has no third trochanter. 



The astragalus has always equal 

 articular facets for the navicular 

 and for the cuboid. The cal- 

 caneum has an articular facet for 

 the fibula, if that bone is fully 

 developed. 



The stomach tends to be complex, 

 and the ca.>cum is small. 



The mamma are few and inguinal, 

 or numerous and abdominal. 



The placenta is diffuse or cotyle- 

 donary. 



There are often bony outgrowths 

 from the frontals. 



There is no alisphenoid canal. 



Perissodactyla — Tapirs, 

 Rhinoceros, Horses. 



The third digit occupies the middle 

 of the foot, is largest, and is 

 symmetrical on itself, so that the 

 line halving the foot bisects the 

 third digit. 



The premolars resemble the 

 molars. 



There are almost always twenty- 

 three dorso-lumbar vertebrae. 



The femur has a third trochanter. 



The astragalus has a large facet 

 for the navicular, a small facet 

 for the cuboid. The calcaueum 

 does not articulate with the 

 lower end of the fibula (except 

 Macrauchenia). 



The stomach is always simple, and 

 the ca'cum is large. 



The mammae are always ingunial. 



The placenta is always diffuse. 



There are never bony outgrowths 



from the frontals. 

 There is an alisphenoid canal 



transmitting the external carotid 



artery. 



