THE ORDER CETACEA. 161 



SPECIES IV. 



THE PHYSETER CYLINDRICUS, 



OR 



THE ROUND SPERMACETI WHALE. 



This species has a hunch on the back ; the teeth are 

 curved and pointed at the top, the spiracles or breath- 

 ing-holes are in the middle of the snout. 



The form and relative situation of the trunk and head, 

 the position of the spiracles, the relative length of 

 the jaws, the number and structure of the teeth, and 

 especially the size of the dorsal fin, present difTerences 

 sufficiently distinguishing this from the following species. 

 The body is cylindrical from the extremity of the snout 

 to a line drawn perpendicular to the place where the penis 

 is inserted, and from thence to the tail fin it gradually 

 diminishes. The head is at least one-third of the whole 

 length of the body. The profile of the head presents a 

 kind of parallelogram. The jaws are nearly of equal 

 length. On each side of the lower jaw there is a row 

 of twenty-five curved, sharp-pointed teeth. The breath- 

 ing-holes are placed in the centre of the superior ex- 

 tremity of the snout. The dorsal fin is replaced by a 

 hunch, eighteen inches high, and four inches and a half 

 long at the base. The tail fin is divided into two lobes, 

 forming a kind of crescent. One of this species is de- 

 scribed by Anderson forty-eight feet long, twelve of per- 

 pendicular height, and thirty-six in circumference at its 

 greatest thickness. 



The colour of this whale is uniformly blackish. It 

 inhabits the Arctic Seas, and the northern parts of the 

 North Atlantic Ocean. 



M 



