CLASS PISCES. 177 



A fossil species of this subdivision has also been 

 discovered at Mount Bolca *. 



Psettus, Commers. // *&?* 



Figure similar to that of a Platax, but the teeth 

 are very small and crowded, and the ventrals reduced 

 to a single small spine, without soft rays. 



The form of some is elevated 2 ; that of others 

 round or oval 3 . They are all from the Indian Ocean. 



Pimelepterus, Lacep. 



Distinguished from all other fishes by a single range of 

 teeth placed in a horizontal base or heel, on the an- 

 terior edge of which is a part vertical and trenchant. 

 The body is oblong, the head obtuse, and the fins 

 thickened by the scales which cover them, from which 

 circumstance their name is derived 4 . They are oval, 



1 Ittiol. Veron. pi. iv. and vi. 



2 Psett. Sebce, Cuv., Chcelodon, rhombeus, Bl., Schn., Seb. III. 

 xxvi. 21. Ps. rhombeus, Cuv., or Scomber rhombeus, Forsk., or 

 Centrogaster rhombeus, Gm. or Ccntropode, rhomboidal Lacep., 

 Russ. 59. 



3 Psett. Commersonii, Cuv., or Monodactyle falciforme, Lacep. II. 

 v. 4. and iii. 131. which very probably does not differ from the 

 Chcet. argenteus, L., or Acanlho'pode, argente, Lacep. 



4 Pimelepterus (fat fin). This genus of Lacepede, iv. 429. 

 formed from Bosc, is the same as that of Xister.es, v. 484. formed 

 from Commerson ; and there is every reason to believe that the 

 Dorsuaire, Lacep., v. 482. which is certainly identical with the 

 Kyphose, iii. 114. may very possibly also be the same as the 

 Xisterus. 



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