42 



a linear groove five inches and a half long, running up from 

 the front of the snout, and which probably marks the place 

 of the bottom of the sockets, which are formed deep in the 

 gum of the upper jaw, for the purpose of receiving the points 

 of the teeth of the under jaw. 



The palatines are small and quadrilateral. The ptery- 

 goideans very large, form two angular apophyses behind, 

 separated from each other by a deep emargination of an 

 elliptical form. 



The lower jaw is a singular contrast to the upper ; the 

 former being as slight and fragile as the latter is massive and 

 strong. So weak is the connection of this under jaw with the 

 skull, that the articulating condyles are scarcely to be detected. 

 The broad branches are nearly as thin as paper, and although 

 the sides are reflexed inwardly, as in dolphins, the doubling, 

 so as to form the hollow tube, does not occur as in them, near 

 the base of the jaw, but within three inches of the symphysis. 

 Each triangular branch, which at the articulating base is 

 semicircular and about four inches high, and convex on the 

 outside, is, from its extreme thinness, almost transparent. 

 The symphysis, which is short in comparison to that of the 

 genus Catodon, is boat shaped and carinated. From its sides 

 project horizontally about thirteen teeth, curved gently 

 upwards on each side. The longest of these is situated about 

 the middle of the symphysis, and is about one and a quarter 

 inch long. They have all single roots implanted in single 

 sockets. They are all about half hollow, as in the true 

 sperm whales, but being so much longer, thinner, and sharper 

 in proportion, give the animal a quite different aspect, and 

 perhaps a more ferocious one. Nevertheless, so extremely 

 feeble an under jaw demonstrates that the long sharp teeth 

 serve merely for the purpose of retaining the weak mollusca 

 which, no doubt, form this creature's prey. 



