4. PETEOEHrNCHTJS. 



347 



"La maohoire inferieure est assez haute en arriere, fortement 

 bombee sur le cote, etroite en avant. La peau des gencives est noire, 

 toute la surface est couverte de petites losanges en saillie, qui la 

 rendent raboteuse. Les dents sont en forme de fuseaux; chaque 

 dent a six centimetres et demi de longueur sur deux centimetres et 

 demi de largeur ou d'epaisseur, mais toute la dent est, pour ainsi 

 dire, racine." — Van Beneden, I. c. 



Kg. 69. 



Skull and tooth of Petrorhynchus Indiais, from Van Beneden. 



Misled by M. Van Beneden's description and figure, which are 

 here reproduced, in my paper in the ' Proceedings of the Zoological 

 Society,' 1865, p. 522, I was induced to form Ziphius Indicus into a 

 genus distinct from the Mediterranean and the Cape Whales. Since 

 that paper was prepared M. Van Beneden has visited England and 

 seen the Cape skull, and considers it the same as or very nearly allied 

 to the one he described, and on his return he most kiudly sent to 

 the British Museum and the CoUege of Surgeons a cast of the beak 

 and the front end of the lower jaw of his specimen ; and there can be 

 no doubt that they are very nearly allied, if not specimens of dif- 

 ferent ages of the same species. For the present it is as weU to keep 

 them separate, pointiag ont the distinction between them. In Ziphius 

 Indicus the very largely developed vomer gradually tapers off behind 

 towards the blowers ; in the P. Owpensis it continues nearly of the 

 same thickness to the hinder end, and is there suddenly and per- 

 pendicularly truncated. It is only necessary to compare the two 

 figures to explain how I came to consider them distiact forms. 



