324 WHALES AND DOLPHINS 



FITZROY'S DOLPHIN {Lagenorhynchus fitzroyi). 



This species, Known from the seas off the southern end of 

 South America, is again distinguishable by its colour, there 

 being no very conspicuous external structural features to mark 

 it off from the other members of the genus The original 

 description of the species was founded on a specimen harpooned 

 from the " Beagle " in the Bay of St. Joseph, Patagonia, and 

 measured immediately after capture by Charles Darwin. At 

 the same time a coloured drawing was made by Captain 

 Fitzroy, after whom the species is called. 



The following is based on Waterhouse's original description : 

 The head is conical and arched above. The back is black and 

 the belly white, the pigmented and unpigmented portions 

 blending into each other at their junction. The end ot the 

 snout, a ring round the eye, the edge of the under lip and the 

 tail fin are black. The back fin and flippers are dark grey. 

 A grey streak, recalling that in L. acutus but much broader, 

 connects the flipper and angle of mouth. Above this bar is 

 a streak of white which includes the eye. On the flanks two 

 elongated promontories of pigment, directed backwards and 

 downwards, invade the white, and still another projects upwards 

 and forwards from the junction of the tail stock with the 

 flukes. 



The teeth number 28 pairs in upper jaw and 24 pairs in 

 lower jaw ; they are slightly curved and conical. The length 

 of the original specimen was 5 feet 4 inches. 



Nothing is known of this creature's habits. 



THE DUSKY DOLPHIN {Lagenorhynchus obscurus). 



Fig. 89. 



The Dusky Dolphin is like the White-sided Dolphin in form, 

 but the snout is longer and narrowei and not so distinctly 

 marked off from the " forehead ". The back fin is moderate 

 in size and the concavity of the hinder margin is less than in 

 the White-sided Dolphin. 



The body colour is subject to considerable range of variation. 



The following description is of a specimen taken in South 

 African water, the colour being recorded at the time of capture. 



