1230 THE CETACEANS 



bands. Representatives of this genus are found in most of the temperate and trop- 

 ical seas, and two species have been taken off the British coasts. 



Of the two British species, the white-sided dolphin (Lagenorhynchus 



D 1 h'n acutus), is blackish gray above, and white beneath, with a broad 



band of yellowish brown between the two, in the middle of which is a 



large white patch; while a narrow black band extends from the flukes nearly to the 



line of the back fin, and another runs from the base of the flipper to a point between 



the eye and the mouth; the eye being surrounded by a black ring. The length 



varies from six to eight feet. This species inhabits the North Atlantic and the 



North Sea. It is very rare on the British coasts, although said to be not unfre- 



quently seen off the Orkneys. 



The species figured to represent this genus (L. crutigera} is one 



from the Pacific; which is selected on account of the marked contrasts 

 Beaked 



Dolphin f black and white. It has a short beak, only slightly marked off from 



the skull. In color, the muzzle, the forehead, the back, and the fin, 



flippers, and flukes are black; while a broad black band runs from the eye and the 



THE PACIFIC SHORT-BEAKED DOLPHIN. 

 (From True, Bulletin of the U. S. National Museum, 1889. ) 



base of the flipper along each side to the flukes; the other parts of the body being a 

 more or less pure white. 



The second species of this genus which has been met with on the 

 White-Beaked 



Dolphin British coasts is the white-beaked dolphin (Z,. aUrirostris) ; this species 

 resembling the white-sided dolphin in general form, but having a more 

 swollen head, a narrower and more sloping back fin, and longer flippers. It takes 

 its distinctive name from the fact of the muzzle, including the extremities of both 

 jaws, being white, more or less tinged with gray. The upper parts are black, the 

 sides grayish, and the under parts white, frequently of a creamy hue; while there 

 are three more or less distinctly defined whitish areas on the flanks, placed one be- 

 hind the other, and more or less mottled w-ith darker tints. There is also a similar 

 light area behind the blow T hole on the back, and another near the root of the flukes. 

 There is, however, considerable individual variation in regard to the coloration. 

 When freshly- stranded specimens come under observation, the black of the back is 

 often seen to be shot with a rich purplish tint, and the whole coloration is then ex- 

 ceedingly beautiful. There are usually about twenty-six teeth on each side of the 

 jaws, and the length attained by adults is from eight to nine feet. The white- 



