162 ZOOLOGY. 



to that of a Roman war-chariot. The upper jaw pro- 

 jects as a broad and plane surface, tapering slightly as 

 it advances. It accords very closely with the lower- 

 jaw in size, notwithstanding the disparity between the 

 two which the aspect of the entire head would lead us 

 to expect. 



The skeleton of the lower-jaw bears somewhat the 

 shape of a plough. It is composed of two long and 

 heavy bones, rounded and closely united for the anterior 

 half of their length, whilst posteriorly they diverge, 

 and increasing in depth at the expense of density, 

 expand each into a broad and thin plate, on which 

 the muscles are implanted. The two bones taper so 

 considerably from behind forwards, that, in a jaw fifteen 

 feet in length, the distance between the articulating 

 surfaces measures five feet, while the breadth of the 

 anterior extremity does not exceed seven inches. The 

 interior of the thickest portions of each bone is divided, 

 by bony partitions, into large cells, filled with a light 

 oily fluid, or spermaceti; an organization which 

 tends much to lessen the specific gravity of their 

 ponderous structure. 



The true and serviceable teeth of this whale are 

 situated only in the lower jaw; and, when the mouth is 

 closed, are received into corresponding sockets in the 

 soft parts, covering the margin of the upper jaw. When 

 in their most characteristic stage of growth, they are 

 raised about two inches above the gum; are acutely 

 pointed; and curved in a direction backward and 

 slightly inward. They are imbedded for a great portion 

 of their length in the bony sockets of the jaw, as well as 

 in the dense white substance, or gum, which rises as 

 an embossed ring around the base of each tooth. The 

 central teeth are of greater length, and thicker, than 



