Dr..J. E. Gray on a new Species of Pilot-Whale. 321 
specimens of both sexes have been recorded as caught on the British 
coast. Atthe present moment there is an inclination to regard some 
of the Whales which have been considered species as mere sexes of 
Upper surface of the skull of Globiocephalus incrassatus. 
the same species, simply because the specimen described in one case 
happens to be a male and in the other a female. Thus Delphinus 
micropterus is said to be the female of Ziphius Sowerbiensis, for the 
