146 CETACEA. 



Order CETACEA. 



Form of the body fish-like ; anterior extremities in 

 the form, and with the uses, of fins ; hinder extremities 

 wanting ; tail horizontal ; teeth various, sometimes 

 entirely absent. 



Genus DELPHINUS. 



Both jaws furnished with numerous simple teeth ; snout 

 produced into a beak, separated from the forehead by a 

 depression ; a dorsal fin. 



Subgenus 1. Delphinus. 

 Delphinus Delphis. 



Delphinus BelpJiis, Desm. Mamm. Sp. 758; Bell, Brit. Quad. 

 Common Dolphin. 



Description. — The teeth vary in number according to age, 

 from thirty-two to forty-seven on each side in each jaw ; 

 they are sharp, slightly incurved, and lock with the teeth 

 of the opposite jaw ; the orifice of the ear is scarcely larger 

 than a pin-hole ; the blow-hole is crescent-shaped ; the 

 jaws are nearly of equal length, moderately produced ; the 

 colour is blackish on the back, greyish on the sides, and 

 glittering white beneath ; the female produces a single 

 yomig one at a birth ; while suckhng, the mammary glands 

 are much enlarged, and the teats crested. 



Length, from 6 to 8, rarely 10 feet. 



It is common on the coasts of the British Islands, and is 

 found in aU the European seas, Mediterranean, Baltic, &c. 



