NAKED-TOOTHED FISHES. 285 



points of structure and economy, and therefore 

 not without interest to the naturalist, are of 

 little value ; their flesh being in general rank 

 and glutinous, and unfit for human food. Most 

 of the species are natives of the tropical seas; 

 though an individual occasionally strays into 

 colder chmates. We shall consider them as 

 forming two Families, Tetraodontidce and Balis- 

 tides, 



Family I. Tetraodontidce. 



{Nahed-toothed Fislies.) 



Instead of teeth arranged in some sort of ser- 

 ried order, the fishes before us have them united 

 into masses, presenting externally no trace of 

 individuality, but internally showing a number 

 of parallel thin plates. The form of these masses 

 of teeth resembles that of a parrot's beak, and 

 they are covered with a common coat of ivory-like 

 substance. They are continually renewed by 

 the growth of the component plates, as the sur- 

 faces are worn down by grinding the sea-weeds 

 and crustaceous animals that constitute the com- 

 mon food of the Family. 



Most of the species have the skin covered with 

 prickles, differing in number and strength, and 

 capable of being erected. They are, in general, 

 endowed with the power of inflating the body 

 with air to a remarkable degree. One genus, 

 that of the Sun-fishes (Orthagoriscus), is desti- 

 tute of both these characters ; but it is marked 

 by an equally curious peculiarity of form : the 

 tail being so short, and the posterior termination 



