122 FISHES. 



species abound iu both oceans*. Their form is oval or oblong; we may- 

 separate from them the 



PoMACANTlIUS, CuV., 



In which the form is more elevated; a circumstance resulting from the 

 more sudden rise of the edge of the dorsal f. The only species known 

 are from America. 



Platax 



Have in front of their brush-like teeth a row of trenchant ones, each 

 divided into three points; the body, strongly compressed, seems to be con- 

 tinued into thick, vertical, elevated, and scaly fins, in whose anterior edge 

 some few spines are concealed, so that the whole fish is much higher than 

 it is long; very long ventrals. The whole of the subgenus are found in 

 the Indian Ocean J. 



One species, Ch. arthriticus, Bell. Phil. Trans. 1793, pi. vi, of a 



more orbicular form, is remarkable for the knots or enlargements iu 



some of its interspinals and spinous apophyses §. 



A fossil species of this subdivision has also been discovered at 



Mount Bolca||. 



PsETTUs, Commers., 



Have, with the figui-e somewhat resembling that of a Platax, the teeth 

 small and dense as the pile on velvet, and the ventrals reduced to a single 

 small spine, without soft rays. 



The form of some is elevated^; that of others round or oval**; they 

 are all from the Indian Ocean. 



PlMELEPTERUS, Lcicep., 



Are distinguished from all other fishes by a single range of teeth placed 

 in a horizontal base or heel, on the anterior edge of which is a part verti- 



* American species, Chcct. ciliaris, L, Bl. 214, or Isahelita, Parra, VII, 1, or 

 Chtet, couroruie, Desmar. Dec. Icthyol.; — Chert, tricolor, Bl. 425; Duham. Sect. I\, 

 pi. xxiii, 5. India species, Chat, bicolur, Bl. 20G, 1 ; — Ch. mesoleiicos, Bl., or mesn- 

 mclas, Gm., Bl. 216, 2;—Holoc. amiralis, Cuv., Ren. I, xvi, 92;— C//. annularis, Bl. 

 215, 2;— C/i. imperutor, Bl. IQii—Ch. fasciatus, Bl. 195;— Ch. mcobariensis, Bl. Schn. 

 50, or Geomeiricus, Lacep. IV, xiii, 1; — Hoi. Lamark, Lacep. IV, 531, Reuard, I, 

 xxvi, 144, 145, and several new species. 



t Chat, aureus, Bl. 193, 1, or Chirivita janne, Parra, VI, 2;— Chat, paru, Bl. 197, 

 or Chirivita noir, Parr. A'l, 1; — Ch. ^-cinctus, Cuv., Gua/ierva, Marcgr. 17S; — Ch. 

 urcuatus, L., Bl. 204, 2. 



I Chat, vespertilio, Bl. 199, 2;—Ch. ieira, lh.l;—Ch. guttulatus, Cuv., Ren. II, 

 xxiv, 129. 



§ It is also the Ch. pentacanthe, Lacep. IV, xi, 2, and the Ch. orbicularis, Forsk., 

 or Acanlhinion orbiculuire, Lacep. IV, 500. 



II Ittiol. Veron. pi. 4 and 6. 



^ Psett. Seba, Cuv., Chatodon rhomheus, Bl. Schn., Seb. Ill, xxvi, 21;— Pi. 

 rhombeus, Cuv., or Scomber rhombeus, Forsk., or Centrogasler rhombeus, Gm., or Cen- 

 iropude rhombo'idal, Lacep., Russ. 59. 



** Psett. Commersovii, Cuv., or Monodactyle fulciforme, Lacep., II, v, 4, and III, 

 131, which very probably does not difl'er from the Chat, argenletis, L., or Acantho- 

 pode argente, Lacep. 



