694 



MAMMALIA. 



cealed. At night they come on land and browse on grass and 

 herbage. The skin is extremely thick, with a few hairs restricted to 

 the snout, head, neck, and tail. There are four toes on each foot, 

 all reaching the ground. The rootless incisors continue growing ; 



2-3, M3 

 so do the large curved canines ; the dental formula is 



i-3> 143 



The stomach has three chambers ; there is no coecum. 

 Suidse : The Old World boars and pigs, characterised by the mobile 

 snout and terminal nostrils. There are four well-developed digits 

 on the narrow feet, but the second and fifth do not reach the 



FIG. 249. Foot of Ox. 



a., Astragalus ; c., os calcis ; 

 m.t. t cannon bone (fused third 

 and fourth metatarsals) ; ph., 

 phalanges. 



FIG. 250. Fore leg of Pig. 



/i., Humerus ; r., radius ; u., ulna; 

 ., scaphoid ; /., lunar ; c., cuneiform ; 

 t., trapezoid ; ;;/., os magnum ; ., 

 unciform ; 2-5, digits. 



ground in walking. The incisors are rooted, the upper canine 

 curves outwards or upwards. The stomach is almost simple, but 

 has more or less of a cardiac pouch ; there is a caecum. 



3*43 2I2 3 



Examples : Stis, ; Babirusa , the male with remarkable 



3 J 43 3*23 



canines, the upper pair growing upwards from their base 



