PORPOISE. 461 



by Camper and by Dr. Jackson of Boston, have been 

 generally overlooked, and consequently Dr. Gray, on 

 first observing them, regarded them as the characters of 

 a new species, which he named Ph. tuberculifera. 



The colour of the upper parts is dusky or black, be- 

 coming gradually lighter on the sides and nearly passing 

 into white on the belly ; the flippers are tinged with 

 brown. 



The teeth vary in number from twenty to twenty-six on 

 each side of either jaw, and differ in form from those of 

 most of the Delphinidtv ; instead of being conical, they 

 are enlarged, compressed and truncated at the apex, with 

 a contracted neck below. The rostrum of the skull is 

 broad, the cervical vertebrae are usually anchylosed ; the 

 whole number of vertebrae is sixty-five and of ribs thir- 

 teen pairs. 



The Porpoise attains a length of from four to five feet. 



