58 



which he only knew by Sir Robert Sibbald's figure. The 

 truth is, that the Ewphysetes comes much closer in external 

 appearance to the black fish than to the sperm whale. It in 

 a manner proves the existence, now or formerly, of such a 

 species as Sibbald and Fabricius described from the northern 

 part of the German Ocean. Like the Euphysetes, the 

 black fish is said to have a round head with a depressed 

 and truncated snout; it had also a dorsal fin, and its 

 bloAvhole was situated on the middle of the head. Now, 

 as the skeleton of the Euphysetes comes so near to that 

 of Catodon, it is impossible that Mr. Gray can be wrong 

 in considering the black fish (the Physeter Tursio of 

 Linnseus) to belong truly to the family of sperm whales. 



The known genera that belong to the family of Catodontidce 

 may by their external appearance be shortly characterized as 

 follows, viz. : — 



No dorsal fin, but only 

 a hump instead. Blow- 

 hole at the extremity 

 of snout. 



Dorsal fin. Blow- 

 hole on middle of head. 



1. Catodon. 



2. KOGIA? 



3. Euphysetes. 



4. Physeter. 



Head between a third 

 and fourth of the whole 

 length. 



Head moderate, tri- 

 angular, and pointed in 

 front ? 



Head moderate, like 

 that of a dolphin, and 

 truncated in front. 



Head half length of 

 rest of skeleton ? Blow- 

 hole covered by an 

 operculum or flap ? 



But of anatomical characters by which we may separate the 

 Euphysetes from all other described genera of the sperm 

 whale family, there is none so striking as that ridge of bone 

 which divides the back part of the spermacetic cavity into two 

 lesser cavities nearly equal in size. 



