^^^ PISCES. 



pelvis, which is completely hidden under the skin and is without 

 that spinous projection observed in the other Balistes.(l) 



Triacanthus, Cuv. 

 Is distinguished from all other Balistes by a kind of ventrals, each 

 of which IS supported by a single large spinous ray, adhering to a 

 non-salient pelvis. The first dorsal has three or four small fpines 

 behind a very large one. The skin is crowded with small scales, 

 and the tail is longer than in the other subgenera. 



But a single species is known; it inhabits the Indian Ocean.(2) 



OsTRAcioN, Lin. 



The head and body of these fishes, instead of scales, are covered 

 with regular bony plates soldered in such a manner as to form a sort 

 of inflexible shield, which invests them, so that the only movable 

 parts are the tail, fins, mouth, and a sort of small lip with which 

 the edge ot their gills is furnished, all passing through holes in this 

 coat ot mail. The greater number of their vertebrae are also sol- 

 dered together, and each of their jaws is armed with ten or twelve 

 conical teeth. The external branchial aperture is a mere slit fur- 

 nished with a cutaneous lobe, but internally we find an operculum 

 and SIX rays. Both the pelvis and ventrals are wanting, and there 

 are but a single dorsal and ventral, both small. 



They have but little fleshj their liver, however, is larije and pro- 

 duces much oil. Their stomach is membranous and large, some of 

 them are considered poisonous. 



They may be divided according to the form of their body and the 

 spmes with which it is armed, we are not certain, however, that 

 there is not, in this respect, some sexual difference.(3) 



urlfli rr;? ':u''t- ^'^-^'^ "^^^^^^^^^^ ^ ^^' -^^-^^ ^^ ^'^-nt, 



three preceding ones;-5a/. Kklnii, M so. II ^pi H 'f 2 ^f '"^Z^'^";;'^- 

 Cuv., Ren., II, part of pi. xlii, f. 284. ^ ' ^'^^^^^'''"^. 



(2) al. biacukatus, HI, 148, 2 



pJ^Zr" ^P^'^^^^"'^" ^'^-^ -^.?--^ -11 be described in our Hist, des 



4th. Triangular, the ridges armed with spines. Osi. siellifer Schn Q- fh. 

 same as the 0.^. bicuspis, Blumenb., Abb., 58. ^ ' ' ^' ' '^^ 



