FAUNA AMERICANA. 293 



Characters. Dental formula. From eighteen 

 to twenty teeth on each side of the lower jaw. 



Superior jaw broad, elevated, without corneous 

 laminae, without teeth, or furnished with small 

 teeth nearly concealed by the gums ; inferior jaw 

 elongated, narrow, corresponding to a groove in 

 the upper, and armed with thick and conical teeth 

 entering into corresponding cavities in the oppo- 

 sing jaw. 



Blowing holes united, and situated near the 

 end of the upper part of the snout. 



A dorsal fin in some species ; a mere eminence 

 in others. 



Large cavities with cartilaginous septi in the 

 superior region of the head, communicating with 

 various parts of the body by particular canals, 

 and filled with an oil which crystallizes in cool- 

 ing. (Called commonly adipocere, blanc de ba- 

 leine, spermaceti.) 



The Cachalots inhabit principally the Polar 

 Regions, but are found sometimes in temperate 

 regions ; they war with the seals and feed also on 

 Crustacea. 



1. Subgenus, Catodon, Lacep. 



Blowing holes situated completely at the end 

 of the upper surface of the snout. IVo dorsal fin. 



