VNGULATA. 



753 



MANATEE (Manatus}. 



DUGONG (Halicore}. 



Neck vertebrae reduced to six. 

 Abortive incisors (f ) in both sexes. 



Molars (|) six or so at a time, 

 uniform, with square enamelled 

 crowns, and tuberculated trans- 

 verse grinding ridges. 



Prernaxillse almost straight. 



Tail rounded. 



Rudimentary nails on fingers. 



Caecum divided. 



M. australis and M. senegalensis 

 live in the mouths of great rivers 

 which flow into the tropical 

 Atlantic. 



The usual seven neck vertebrae. 

 Two tusk-like incisors persist in 



the male. 

 Molars (f or f, 2 or 3 at a time), 



primitive, with persistent pulps 



and no enamel. 



Premaxillas crooked downwards. 



Deeply notched tail. 



Nailless digits. 



Thick and single caecum. 



H. tabernaculi, E. African coast 

 and Red Sea ; H. dugong, Indian 

 and Pacific Oceans, eastward 

 from the home of the last species 

 to the Philippines ; H. australis, 

 E. and N. Australia. 



The genus Rhytina was toothless, with a slightly crooked snout, 

 small head and arms, and thick naked skin. Steller's sea-cow (R. 

 sielleri] the only known species, from the North Pacific seems to 

 have been exterminated about 1768. The tertiary Halitherium had 

 traces of hind-limbs. 



Order UNGULATA 



Hoofed Animals Artiodactyla, Perissodactyla, Hyra- 

 coidea, Proboscidea, and extinct sub-orders. 



This large and somewhat heterogeneous order in- 

 cludes pigF, hippopotamus, camels, cattle, deer, tapirs, 

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

 types. 



They are terrestrial, and for the most part herbivorous 

 animals. 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. 



In the typical Ungulates the feet are never plantigrade. 

 In modern types there are never more than four functional 

 toes. The os magnum of the carpus articulates freely with 

 the scaphoid. The brain is well convoluted. The testes 

 descend into a scrotum. The uterus is bicornuate. The 



