PORPOISES AND DOLPHINS. 



57 



with distinct beaks, and remarkable for their strongly-contrasting coloration. They 

 are generally characterised by the head having a short and not very well-defined 

 ploughshare-like beak, although in one species the head is pointed and beakless. 

 The fin and flippers are of moderate size ; and the tail has very prominent ridges. 

 The teeth are variable in size and number ; the beak of the skull is flat, and not 

 longer than the hinder part of the same ; and the union between the two branches 

 of the lower jaw is short. The coloration takes the form of two light-coloured 

 areas of variable size on the sides, separated from one another by irregular, oblique 

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

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

 wwte-sided Of the two British species, the white-sided dolphin (Lageno- 



Doiphin. rhynchus acutus), is blackish grey 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 



THE PACIFIC SHORT-BEAKED DOLPHIN. 



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



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

 length varies from 6 to 8 feet. This species inhabits the North Atlantic and the 

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

 quently seen off the Orkneys. 



Pacinc Short- The species figured to represent this genus (L. crucigera) is one 



Beaked Dolphin, f rom the Pacific, which is selected on account of the marked contrasts 

 of black and white. It has a short beak, only slightly marked off from the skull. 

 In colour, 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 base of the flipper 

 along each side to the flukes ; the other parts of the body being a more or less 

 pure white. 



White-Beaked The second species of this genus which has been met with on 



Dolphin. the British coasts is the white-beaked dolphin (L. albirostris) ; 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 grey. The upper-parts are black, the 

 sides greyish, 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 



