ORDER CETACEA. 439 



upper, is armed on each side with a range of conical 

 or cylindrical teeth, which enter into the corre- 

 sponding cavities of the upper jaw when the mouth 

 is closed. The upper part of the enormous head 

 consists only in large cavities, covered and separated 

 by cartilages, and filled with an oil which fixes when 

 it cools, and is well known in commerce under the 

 absurd name of spermaceti. It is this which renders 

 the Cachalots an object of research, for their body 

 is not supplied with much fat. These cavities are 

 very different from the true cranium, which is rather 

 small, placed under them, and contains the brain as 

 usual. It appears that canals filled with this sper- 

 maceti are distributed in many parts of the body, 

 and communicate with the cavities which fill the 

 mass of the head. They are even interlaced in the 

 usual fat found throughout the skin. 



The odorous substance so well known by the 

 name of ambergris, appears to be a concretion 

 formed in the intestines of the Cachalots, and prin- 

 cipally in the caecum. It more especially takes 

 place in certain morbid states of the system. 



The species of Cachalots are any thing but well 

 determined. The Macrocephalus of Shaw and 

 Bonnaterre, which seems to be the most com- 

 mon, has only a callous eminence instead of a 

 dorsal fin. In the lower jaw, on each side, are 

 from twenty to three-and-twenty teeth, and 

 there are some small conical ones hid in the 

 gums of the upper. The spiracle is single, and 

 not double as is usual with most part of the 



