434 CLASS MAMMALIA. 



The species which have teeth, have them all of a 

 conical form exactly resembling. They do not chew 

 their food, but swallow rapidly. 



Two small bones, suspended in the flesh near the 

 anus, form the only vestige of posterior extremities 

 which remain. 



Many have on the back a vertical fin of tendinous 

 substance, but not supported by bones. Their 

 eyes, flatted in front, have a thick and solid sclero- 

 tica. The tongue has only smooth and soft tegu- 

 ments. 



They may be again subdivided into two small 

 tribes. Those whose head is in the ordinary propor- 

 tion with the body, and those which have it immeasu- 

 rably large. 



The first comprehends the Dolphins and Narwhals. 



The Dolphins (Delphinus, L.) 



Have teeth in both jaws, all simple, and almost 

 always conical. They are the most carnassial, and, 

 in proportion, the most cruel of the order. They 

 have no caecum. 



The Dolphins, properly so called, (Delphinus, Cuv.) 



Have the throat forming in front of the head, a beak 

 more slender than the rest. 



The Common Dolphin {Delphinus Delphis. L.) Lacep., 

 Cet. pi. xin., y, i. 



With depressed beak, and armed on each side 



