630 SIR SIDKET HARMER ON COMMERSON's DOLPHIN 



Colour. — Jet-black and pure white, the principal white area 

 shading to some slight extent through grey to the black areas in 

 front and behind (as in Moreno's pi. ix. fig. 1), but the junctions 

 of the two colours othei'wise very sharply marked. The black 

 occurred on the whole of the head and lower jaw (interrupted 

 ventrally by a pear-shaped, median, white area on the throat), 

 extending backwards obliquely from the sides of the head to the 

 pectoral fins, which were black on both surfaces, and was 

 continued across the ventral side as a broad band, behind the 

 white marking on the throat, this band giving oft' an acutely 

 pointed median prolongation backwards, between the flippers. 

 The tail, including the flukes on both surfaces, was black all 

 round, for nearly a foot from its emargination, and this colour 

 was continued forwards obliquely on the back' beyond the dorsal 

 fin, but separated by a white interval even in the mid- dorsal line 

 from the black of the head, A large heart-shaped black area 

 surrounded the reproductive opening, and was observed by 

 Mr. Hamilton in another male specimen examined by him. The 

 white part of the skin consisted of (a) the median ventral area on 

 the throat, (&) the main white area encircling the body obliquely, 

 much more developed ventrally than dorsally, and including 

 most of the ventral and lateral regions of the body. 



Mr. Yallentin's photographs (PI. I. fig. 3; PI. II. fig. 1), one 

 of which shows that the specimen was a male, correspond in 

 every essential detail with the above description. Mr. Adams's 

 sketch (D), which represents animals seen in the sea, agrees closely 

 with the others, but from the conditions under which it was 

 made, it is not surprising that it does not show any black area 

 round the reproductive opening. His photograph shows two 

 living animals in the air, as seen from the ship, and it suggests 

 the idea of a Porpoise " moitie blanc, moitie noir," as described 

 by Quoy and Gaimard. 



Neither Moreno nor Bruce shows a broad black marking round 

 the reproductive opening. Moreno's ventral view indicates, 

 however, a narrow, longitvidinal, black mark in this situation, its 

 posterior third being nearly constricted ofi" from the front 

 poi'tion. The specimen was a female, and the question arises 

 whether the individuals of this sex normally have a ventral black 

 marking narrower than that of the male. One of Bruce's figures 

 (the lowest in the Plate) of an animal of unrecorded sex gives 

 aome indication of a constricted, narrow marking like that shown 

 by Moreno. 



External form. — The head of A had no beak distinctly outlined 

 from the remaining portion, but was nearly conical. The dorsal fin 

 had an elongated base, and was low and rounded, with but little 

 indication of a falcate shape. The flippers were also more 

 rounded at their ends than in most Dolphins. These characters 

 point to Cephalorhynclius (cf. True, 1889, pp. 108, 176), and this 

 conclusion is confirmed by the cranial characters. 



