PISCES. 325 



68. TETRODON Jaws divided in the middle, so 



as to present the appearance of four teeth, two above and 

 two below : skin rough, with small slightly projecting 

 spines : body capable of inflation. 



69. ORTHAGORISCUS Jaws undivided: body 



very much compressed, short, truncated behind; rough, 

 but without spines ; not capable of inflation : dorsal and 

 anal fins high and pointed, uniting with the caudal. 



ORDER V. SCLERODERMI. 



Snout very much produced, of a conical or pyramidal 

 form ; mouth small, with distinct teeth in each 

 jaw : skin generally scabrous, or clothed with large 

 scales. 



70. BALISTES Eight teeth, forming a single row, 



in each jaw : body compressed ; covered with large, hard, 

 rhomboidal scales, not overlapping one another : first dorsal 

 with three spines ; the first much the largest, the third very 

 small, and remote from the others ; extremity of the pelvis 

 projecting; armed with prickles. 



(II. CARTILAGINEI.) 



Skeleton cartilaginous : bones soft, and destitute of 

 fibres : sutures of the cranium indistinct : maxillary 

 and intermaxillary bones either wanting or rudi- 

 mentary ; the palatines, or vomer alone, supplying 

 their place. 



