PORPOISES AND DOLPHINS 3*5 



L. borealis of the North Pacific is more generally pigmented, 

 but has a white area on the under surface between the nippers 

 and a strip of white extending from it to the flukes. In this 

 species the flippers are pi fe mented. 



The length of L. peronii is stated to be nearly 6 feet, and of 

 L. borealis slightly over 8 feet. 



The teeth are small, sharply pointed and numerous, 43 pairs 

 in the upper and lower jaws of L. peronii, and 44 pairs in the 

 upper and 47 pairs in the lower jaws of L. borealis. 



Lillie, writing of L. peronii in the 'British Antarctic ("Terra 

 Nova ") Expedition Report onCetacea ', states that he observed 

 a pair on two different occasions playing under the bows of 

 the ship. " They seemed to roll over more than the other 

 dolphins we saw. On October 20th the L. peronii came with 

 a herd of Dusky Dolphins, but they kept separate." 



Genus Cephalorhynchus. 



In the genus Cephalorhynchus are included a number of 

 southern, mostly cold-water dolphins of small size, porpoise-like 

 form and striking black and white coloration. The beak, if it 

 justifies such a name, is only very indistinctly marked off 

 from the rest of the head, and in profile its outline merges 

 almost imperceptibly into that of the " forehead " In all, 

 about a dozen species have been included in the genus, several 

 of them known only from skeletons or skulls. Description 

 here will be confined to the better-known members of the 

 group. 



HEAVISIDE'S DOLPHIN {Cephalorhynchus heavisidei). 

 Fig. 83 



The type of the genus, this conspicuously marked form 

 recalls in its coloration the Killer Whale. The shape of the 

 head is as described in the preceding paragraph. The dorsal 

 fin is triangular and the flippers ovate in shape as in the 

 Common Porpoise. The tail flukes are rather narrow and 

 tapering and the concavity of the hinder margin is pronounced 



The back is black and the under surface from chin to tail- 

 flukes white or yellowish white. Black and white are sharply 



