390 Dr. J. E. Gray on the Geographical 
in the form and length of the beak compared with the brain- 
cavity, in the a being grooved on each side, in the num- 
ber and size o 
In the same way, entire blackness seems to be characteristic 
of the genera Pseudorca, Neomeris, and some other Cetacea. 
ere is no reason why there should not be as many kinds 
of whales in the Southern Ocean as in the northern seas, 
especially when we consider how much more extensive it is 
compared with the land than in the northern regions. 
strongly suspect that the reason the number of species ap- 
pears to be less arises from their having been only lately 
studied, and consequently the very im sect knowledge we 
have of the inhabitants of that region. 
