216 



FISHES 



fishes. There may be a deposition of bony matter in cer- 

 tahi places —for example in the jaws and the vertebral col- 

 umn. The jaw is lart^e au(_l strong ami furnished with many 

 teeth. The mouth of most sharks is on the under side of 

 the head some httle distance back of the end of the snout. 

 Consequently, a shark usually turns on its back when seizing 

 its piey The gill openings aie from five to seven in number, 



on each side of the 

 neck (see the hammer- 

 headed shark, Fig. 

 151), and are simply 

 long, narrow, uncov- 

 ered slits. The larg- 

 est of all fislies is 

 the gi-eat liasking 

 shark which attains a 

 length of forty feet. 

 Some sharks repro- 

 duce by eggs which 

 are of considerable 

 size and furnished 

 with a hard chitinous 

 shell, often bearing 

 several long filaments 

 whicli seem to serve for attachment to sea^A'eeds and the like. 

 In general, a ray, or skate, has a broad, flat body usually 

 ending in a long, slender tail (Fig. 152). It s\'\ims close to 

 the bottom of tlie sea for the most part, and feeds upon 

 crabs, small fisli, etc. It does not, like the shark, turn over 

 to seize its [)iey, but swims quietly over a fish and qiuckly 

 settles down upon it, holding it fast with the broad bod\ 

 and strong jaws. 



I'll, 



-Stiiiii; I n (nmmrmlv culk^l 



