3l6 WHALES AND DOLPHINS 



marked off from each other. On the sides the black pigmen- 

 tation is invaded by upward extensions of white. Some 

 variation exists, but the lobes of white, one in front and one 

 behind the flipper, appear to be fairly constant, as is also the 

 longer, more conspicuous prolongation originating near the 

 ventral surface about half-way along the body and projecting 

 obliquely backwards towards the tail. 



The teeth are small, pointed and moderately numerous, 

 25 to 30 pairs in upper and lower jaws. 



The adult length is about 4 feet. This species is known 

 from the neighbourhood of the Cape of Good Hope. 



HECTOR'S DOLPHIN {Cephalorhynchus hectori). Fig. 84. 



This species is very like Heaviside's Dolphin, but the head is 

 more elongated and the beak is indistinctly defined. The 

 flippers have almost parallel upper and lower margins and 

 bluntly rounded tips. The back fin is low. rounded at the tip 

 and reclines backwards. 



In its distribution the body colour is strikingly like that of 

 Heaviside's Dolphin, but on the under surface in the region of 

 the flippers the pigment is continued from one side of the body 

 to the other, and a promontory from this black area extends 

 forward to end just behind the under surface of the head. 

 The oblique extension of white into black on the flanks is 

 very like that found in Heaviside's Dolphin, but, like the 

 forward-extending bar of pigment below it, is more attenuated 

 in shape. The teeth number 30 to 32 pairs, and the total 

 body length is about 6 feet. This species is found off New 

 Zealand. 



WHITE-BELLIED DOLPHIN {Cephalorhynchus albiveniris). 



C. albiveniris is a rare South American species. Its form is 

 like that of previously described species with rounded dorsal 

 fin, short flipper and very concave posterior border to tail 

 flukes. 



Most of the body is darkly pigmented, but there are patches 

 of white on the throat, behind the flippers and on the belly. 

 It grows to a length of about 4 feet 6 inches. 



