MANUAL OF NATURAL HISTORY. 19 



3. Family. — Dolphins (Delphinidse). Head small, 



short, and rounded, or lengthened into a 

 beak ; jaws generally furnished with a num- 

 ber of conical teeth ; with or without a dor- 

 sal fin. For the most part of comparatively 

 small size, and in form taper towards each 

 extremity. 



II. S UB-ORDER..— Herbivorous-Cetaceans 

 (Herbivora). 



Grinders with flat crowns ; two mammae on breast ; 

 hairy whiskers ; orifices of nostrils pierced at end of 

 muzzle. 



4. Family. — Manatees (Manatidse). Skin thick, and 



coarse-grained, with a few scattered hairs ; 

 head conical; muzzle large and fleshy, two 

 tufts of stiff bristles at its sides ; upper lip 

 cleft ; mouth moderate ; nails on edges of 

 swimming paws ; tail terminated by a length- 

 ened oval fin ; grinders |^| ; no cutting or 

 canine teeth in adult. 



5. Family. — Dugongs (Halicoridse). Skin smooth, 



with a few scattered hairs ; head small in 

 proportion, and of a peculiar form, owing, in 

 great measure, to the large, thick, and trun- 

 cate upper lip, forming a blunt thick snout, 

 truncated portion furnished with bristles ; 

 nostrils on summit of upper jaw at the point 

 where it is bent down ; two cutting teeth in 

 upper jaw in form of tusks, grinders *rj ; 

 caudal fin bilobed. 



