348 WHALES AND DOLPHINS 



ww. Unpigmented area between 

 flippers on imder surface 



Heaviside's Dolphin (p. 315). 

 wv. Unpigmented portions of body 

 entirely restricted to ventral 

 surface. No elongated promon- 

 tories of white on flank 



White-bellied Dolphin (p. 316). 

 00. Size j\ to 30 feet. 



x. Head long conical. Crowns of teeth 

 distinctly corrugated. 



Rough-toothed Dolphin (p. 331). 

 xx. Head blunter, not conical. 



Y. Teeth absent in upper jaw ; those in lower 

 jaw few in number and limited to front 

 portion of jaw. Colour grey, deepening 

 to black on fins and tail 



Risso's Dolphin (p. 301). 

 yy. Teeth in both jaws. 



z. Flippers very long and narrow. Teeth 

 limited to forward part of jaws. 

 Head conspicuously bulging in front 



Pilot Whale (p. 303). 

 zz. Flippers of moderate length. Head not 

 conspicuously bulging. Teeth not 

 restricted to forward part of jaws. 

 a. Flippers rounded in outline. Body 

 colour conspicuously black and 

 white. Teeth powerful, elliptical 

 in cross section 



Killer Whale (p. 289). 

 aa. Flippers tapering to a point. Teeth 

 circular in cross section. 

 b. Colour entirely black. Size up to 

 18 feet. Teeth diameter \ to 

 I inch . False Killer (p. 294). 



bb. Colour slate blue. Size up to 

 7! feet. Teeth diameter \ inch 



Irawadi Dolphin (p. 299). 

 NN. Head with beak marked off from " forehead ". 

 c. Beak short or ploughshare shaped. 2 to 3 

 inches in length. 

 d. Body size moderately large, 9 to 12 feet. 

 Teeth few, 20 to 22 visible in each jaw, 

 f inch diameter 



Bottle-nosed Dolphin (p. 326). 



