264 



Dzicllcrs of the Sea and Shore 



but some will {ctd on fishes, for they have often been 

 observed feasting among herring shoals and schools 

 of an Arctic species {Osmenis arct'iciis). 



When we turn to the toothed whales, we find not 

 merely a difference in the dental equipment but there is 

 a marked change in the food habits and generally in 

 geographical distribution as well. This group, the 

 Odontoceti, is a numerous one, the most noteworthy of 

 which are the sperm whales, dolphins, and porpoises. 

 The largest of these is the sperm whale {Physeter 

 macrocephaliis) , known sometimes as the cachalot, 



SPERM WHALE. 



which attains to a length of over sixty feet. Its char- 

 acteristic gigantic head, with the straight, blunt fore- 

 head, is an enlargement caused by the presence of a 

 huge mass of waxy substance {spermaceti) in this 

 region. The mouth is on the under side of the head, 

 and is somewhat behind the end of the snout. The 

 teeth are large and conical, and confined to the long, 

 narrow lower jaw. They number about twenty-five 

 on each side, and are of a very good quality of ivory. 

 In comm.on with several of the other toothed whales 

 it lives mostly on squids and cuttlefishes; nevertheless, 

 fishes of considerable size are often a preponderant 

 part of its diet. It is likely that the cephalopods it 



