550 MANUAL OF ZOOLOGY. 



in shape. The head is by no means so disproportionately large 

 as in the former families, usually forming about one-seventh of 

 the entire length of the body. 



Fig. 214. — The common Dolphin {Delpkinus delphis). 



The most noticeable members of this family are the tnie 

 Dolphins, the Porpoises, and the Narwhal. 



The Dolphins have an elongated snout, separated from tlie 

 head by a transverse depression. The common Dolphin (Del- 

 phinus delphis^, fig. 214) is the best-known species. It aver- 

 ages from six to eight feet in length, and has the habit of swim- 

 ming in flocks, often tecompanying ships for many miles. The 

 female, like most of the Cetacea, is uniparous. The Dolphin 

 occurs commonly in all European seas, and is especially abun- 

 dant in the Mediterranean. 



The common Porpoise {Phoccma communis) is the commonest 

 and smallest of all the Cetacea, rarely exceeding four feet in 

 length. The head is blunt, and is not produced into a pro- 

 jecting muzzle. The Porpoise frequents the North Sea, and is 

 commonly seen off our coasts. Another British species is the 

 Grampus {Phoccena orca), but this is much larger, attaining a 

 length of from eighteen to twenty feet. Nearly allied to the 

 Grampus is the so-called " Caing " Whale, or, as it is some- 

 times termed, the " Bottl'e-nosed " Whale {Globicephalus or 

 Phoccena globiceps). This species occurs not uncommonly 

 round the Orkney and Shetland Islands, and attains a length 

 of as much as twenty-four feet. It is gregarious in its habits, 

 and is often killed for the sake of its oil. 



Closely alUed to the true Dolphins are two curious Cetaceans, 

 belonging to different genera, but both inhabiting fresh waters. 

 One of these is the Gangetic Dolphin (Platanista Gangetica), 

 which inhabits the Ganges, especially near its mouth. This 

 singular animal is characterised by the great length of its 

 slender muzzle, and by the small size of the eyes. It attains 

 the length of seven feet, and the blow-hole is a longitudinal 

 fissure, and therefore quite unlike that of tlie typical Del- 



