CHAPTER X. 



Section II. — Size of the head disprojjortioned to 



that of the body. 



Genus Cachalot; Physeter; L. 



GENERIC CHARACTERS. 



The head in these animals is of huge size, form- 

 ing a third, or even half of their entire length. 

 The upper is broad, high, destitute of corneous 

 fringes and teeth, or having short teeth, almost en- 

 tirely concealed within the gums. The lower jaw 

 is elongated, narrow, and armed witli thick conical 

 teeth, which fit into corresponding depressions in 

 the upper jaw. The spiracles are placed at or near 

 the extremity of the superior part of the snout. 

 There is a dorsal fin in some species, in others mere- 

 ly an eminence. In the superior' parts of the head 

 there are large cavities, circumscribed by cartilagi- 

 nous partitions, and communicating with different 

 parts of the body by particular canals. These are 

 filled with an oil that becomes fixed and crystallized 

 on cooling, and is the well known substance sper- 

 maceti. 



The teeth are ovoid and recurved; externally they 

 somewhat resemble ivory, internally they are softer, 

 and ash coloured. They are commonly about sisL 



