FISHES, BATRACHMNS, AND REPTILES 213 



uppermost side (fig. 172). The members of the great 

 mackerel tribe swim in the open sea, often in great 

 schools. Largest and swiftest of these is the swordfish, 

 in which the whole upper jaw is grown together to form 

 a long bony sword, a weapon of offense that can pierce 

 the wooden bottom of a boat. 



Many of the ocean fishes are of strange form and ap- 

 pearance. The sea-horses (fig. 174) are odd fishes, cov- 

 ered with a bony shell, and with the head shaped like 

 that of a horse. They are little fishes, rarely a foot long. 





t: 



-*^fciS»^ 



^^ -V 



^c^-. 



4" 

 V 



till' I ■^'- 



h 





Fig. 172. — The winter flounder, Pseudophiironcctds anuricaniis. (After 



Goode. ) 



and cling by their curved tails to floating seaweed. The 

 porcupine fishes and swell fishes have the power of filling 

 the stomach with air, which they gulp from the surface. 

 They then escape from their pursuers by floating as a 

 round spiny ball on the surface. The flying fishes leap 

 out of the water, and sail for long distances through the 

 air like grasshoppers. They cannot flap their long pec- 

 toral fins, and do not truly fly, but strike the anal fin 

 with great force against the water in making a leap so 

 that they move swiftly, and thus escape their pursuers. 

 In its structure a flying fish differs little from a pike or 

 other ordinary fish. 



