56 



FILE-FISH. TRUNK-FISH. 



FIG. 278. BALISTES PJJNCILLIGERUS. 



the surface, or in the neighbourhood of rocks. Some of them 



are remarkable for the appendages with which the body is 



furnished, which are 

 especially striking in 

 the Balistes pencilli- 

 gerus ; their use, how- 

 ever, is entirely un- 

 known. The Ostra- 

 cions, or Trunk-fishes, 

 should probably be 

 placed in a distinct 

 family, so remarkably 

 are they distinguished 

 by the mode in whch 

 the body is protected. 



The head" and-, body are covered with plates of bone, soldered 



toge'lrer~ ; 'in such a manner as to form an inflexible cuirass ; 



leading 'only the tail, the 



fid's*", ther'mouth, and a small 



margin of the gill-opening, 



capUble of motion, all of 



which moveable parts pass 



through openings of the 



cuirass. The greater part Fro 279 .__ TjuINK _ FlSH . 



of tbe vertebrae also are 



soldered together. There are no ventral fins, and the dorsal and 



anal are small and are placed far back ; there is little flesh ; but 



the liver is large, and abounds in oil. The surface is often 



armed with spines. No species of these singular Fish are known 



in the British seas. 



