540 The True Sharks 



an ordinary whaleboat. The basking shark is known on all 

 northern coasts, but has most frequently been taken in the 

 North Sea, and about Monterey Bay in California. From this 

 locality specimens have been sent to the chief museums of 

 Europe. In its external characters the basking shark has much 

 in common with the man-eater. Its body is, however, rela- 



FIG. 333. Basking Shark, Cetorhinus maximus (Gunner). France. 



tively clumsy forward; its fins are lower, and its gill-openings 

 are much broader, almost meeting under the throat. The 

 great difference lies in the teeth, which in Cetorhinus are very 

 small and weak, about 200 in each row. The basking shark, 

 also called elephant-shark and bone-shark, does not pursue its 

 prey, but feeds on small creatures to be taken without effort. 

 Fossil teeth of Cetorhinus have been found from the Creta- 

 ceous, as also fossil gill-rakers, structures which in this shark 

 are so long as to suggest whalebone. 



Family Rhineodontidae. - - The whale-sharks, Rhineodontida, 

 are likewise sluggish monsters with feeble teeth and keeled 

 tails. From Cetorhinus they differ mainly in having the last 

 gill -opening above the pectorals. There is probably but one 

 species, Rhineodon typicus, of the tropical Pacific, straying north- 

 ward to Florida, Lower California, and Japan. 



The Carcharioid Sharks, or Requins. The largest family of re- 

 cent sharks is that of Carchariidce (often called Galeorhinidcc, 

 or Galeidce), a modern offshoot from the Lamnoid type, and 

 especially characterized by the presence of a third eyelid, the 

 nictitating membrane, which can be drawn across the eye from 



