KEY TO THE PRINCIPAL CETACEA 347 



j j. Head with a distinct short beak. 



M. Black pigment restricted to upper parts of 

 head, back and tail. Length up to 6 feet 



Southern Right Whale Dolphin (p. 314). 

 mm. Black pigment more general, white between 

 flippers and on belly. Length about 

 8 feet 



Northern Right Whale Dolphin (p. 314). 

 11. Dorsal fin present. 



n. Head without distinct beak. 



o. Size small up to 6 feet. 



p. Teeth spade-shaped. 



q. Colour entirely black. Dorsal fin with 

 concave anterior margin and convex 

 posterior border. Teeth 16 or 17 in 

 each row 



Burmeister's Porpoise (p. 310). 

 qq. Colour black and white. 

 r. Dorsal fin triangular. 



s. Black of back and white of belly 

 merging into each other in area 

 of grey on sides 



Common Porpoise (p. 307). 

 ss. Black of back and white of belly 

 sharply contrasted on sides 



Spectacled Porpoise (p. 312). 

 rr. "Dorsal fin concave posterior margin. 

 t. White area on side confined to 

 hinder half of body 



Dall's Porpoise (p. 311). 

 tt. White area on side extending 

 forward beyond insertion of 

 flippers True's Porpoise (p. 311). 

 pp. Teeth conically pointed. 



U. Part of beak between head and dorsal 

 fin unpigmented. Striking piebald 

 appearance 



Commerson's Dolphin (p. 318). 

 uu. Back entirely pigmented. 



v. A distinct promontory of white ex- 

 tending upwards and backwards 

 on flank from white of belly, 

 w. Pigment continued from one side 

 of body to the other on under 

 surface in region of 'flippers 



Hector's Dolphin (p. 316) 



