THE TRUE DOLPHINS 1231 



beaked dolphin inhabits the North Atlantic, the North Sea, and the Baltic, ranging 

 as far northward as Greenland and Davis Strait. Between the years 1834 and 1885 

 a total of nineteen specimens of the dolphin had been taken in British waters, and 

 since the latter date a specimen was taken on the Irish coast in 1887, and a third in 

 the river Colne in 1889. 



THE TRUE DOLPHINS 

 Genus Delphinus 



The true dolphins bring us to the first genus of the second great group of the 

 family, which includes all the forms with distinct beaks, except the short-beaked 

 dolphins just described. The beak is generally distinctly marked off from the fore- 

 head by a V-shaped groove, and in the skull the beak considerably exceeds the 

 brain cavity in length. In the skeleton the first two vertebrae of the neck are united, 

 but the other five remain separate. All the members of the group are of 

 comparatively-small size, most of them not exceeding ten feet in length. Dolphins 

 associate in shoals, and feed mostly on fish, although some of them at least also 

 consume crustaceans and mullusks. 



The common dolphin {Delphinus delphis], which apparently frequents 



D . ,. all temperate and tropical seas, is the typical representative of the genus 



Delphinus, which presents the following characteristics. The beak is 



long, and back fin and flippers are elongated and falcate. In the skull the bony 



beak is long and narrow, and generally about twice the length of the region of the 



brain case. The jaws are furnished with a numerous series of teeth, varying from 



about forty to sixty-five on each side, which are sharply pointed, with their bases 



oval in section. The bony union between the two branches of the lower jaw is 



short. 



The common dolphin has a slender bod}'- and small head; the beak being long 

 and narrow, and the flippers about three times as long as broad, with their extremi- 

 ties pointed. There is considerable individual variation in color, but usually the 

 back is dark gray, the under parts white or whitish, and the flanks marked by vary- 

 ing bands of gray or fulvous. The length of the animal is about seven and one- 

 half feet, and there are from forty-one to fifty teeth in the upper, and from forty-five 

 to fifty-one in the lower jaw. 



There seems no doubt that this species is the dolphin of the ancients, 

 although the pictorial representations on old coins, and the descrip- 

 tions of the habits of the animal which have come down to us from the writers of 

 antiquity are alike untrue to nature. The species is occasionally met with around 

 the coasts of Britain, but it is much rarer off Scotland than in the south. It is not 

 uncommonly captured in fishing nets, and examples have from time to time been 

 exposed for sale in Billingsgate market. Like the other dolphins, this species 

 associates in shoals. "The excessive activity and playfulness of its gambols," 

 writes Bell, " and the evident predilection which it exhibits for society, are recorded 

 by every mariner. Large herds of these animals will surround a ship in full sail 



