DOLPHINS 279 



six pairs of ribs are two-headed and five reach the 

 sternum. 



Cephalorhynchw albifrons. True, is a changed name 

 for Electra clancula, Hector,* and has the pectoral 

 fin falcate and the dorsal fin low and ovate. Teeth, 

 3 1 . Pterygoids long and constricted at base. Length, 

 rather over four feet. 



This species, instead of being black, is grey over 

 the greater part of the body ; the fins are darker than 

 the trunk. 



The next species, Cephalorhynchus hectori (van 

 Beneden),f has an obtusely-pointed pectoral fin ; the 

 dorsal fin is low and ovate ; the beak is slightly 

 marked. Teeth, 30. Vertebrae: D. 14; L. 15; C. 

 27 = 63. 



This New Zealand species is very near to both the 

 last. But the throat and lower jaw are white. It 

 has not the white forehead of C. albifrons. 



The fourth and last species of the genus Cephalo- 

 rhynclms eutropia, Gray| ( = Eutropia dickei, Id.), has 

 thirty teeth in each half of each jaw. Skull larger 

 than in C. heavisidii, with longer and more closely 

 approximated pterygoids. 



This species is only known from a skull from the 

 coast of Chili. Sir William Flower, as well as Mr. 

 True, pronounce this form to be quite distinct. 



* Tr. New Zeal, hist., v., 1873, p. 160. 



t Bull. Roy. Acad. Belg. (3), i., iSSi, p. 877. 



\ Proc. Zoo 1. Soc., 1849, p. i. 



