THE ORDER CETACEA. 133 



ellipse, and then a rhombus at the head to the junction 

 of the tail. At the distance of twelve or fourteen inches 

 from the tail, the perpendicular diameter is about twelve 

 inches, the transverse diameter about seven. The back 

 and belly ridges run half way across the tail or more ; 

 and the edges of the tail in the same way run six or 

 eight inches along the body, forming ridges on the sides 

 of the rump. After a very slight elevation at the blow- 

 hole, the outline of the back forms a regular curve ; the 

 belly rises, or seems drawn in, near the vent, and ex- 

 pands to a perceptible bump about two feet from the 

 genitalia. From the neck, three or four feet backward, 

 the back is rather depressed and appears flat. 



The head is about one-seventh of the whole length of 

 the animal ; it is small, blunt, and of a paraboloidal 

 form. The mouth is small, and not capable of much 

 extension. The under lip is wedge-shaped. The eyes 

 are small, the largest diameter being only an inch, and 

 are placed in a line with the opening of the mouth, 

 about thirteen inches from the snout. The spiracle, or 

 blow- hole, which is directly over the eyes, is a single 

 opening, of a semicircular form, about three inches and 

 a half in diameter or breadth, and an inch and a half ra- 

 dius or length. The fins, which are twelve or fourteen 

 inches long and six or eight broad, are placed at one- 

 fifth of the length of the animal from the snout. The 

 tail is from fifteen to twenty inches long, and three to 

 four feet broad. It has no dorsal fin ; but in the place 

 of it, is an irregular sharpish fatty ridge, two inches in 

 height, extending two and a half feet along the back, 

 nearly midway between the snout and tail. The edge 

 of this ridge is generally rough, and the cuticle and rete 

 mucosum being partly wanting, appears as if it had 

 been worn off by rubbing against the ice. 



