FISHES. 



BY CHARLES QIIIARD. 



FAMILY OF PERCID^. 



Genus PEKCICHTHYS, Girard. 

 Gen. ciiar. Body oblong or elongated, compressed, covered with scales of medium derelop- 

 meut, finclj' ciliated upon their posterior margin, Snout rather thick and blunt, overlapping 

 slightly the lower jaw. Two dorsal fins contiguous at their base. Insertion of ventral fins 

 immediately beneath the base of pectorals. Anal fin provided with three spiny rays. Tongue 

 smooth. Upper surftice of head, suborbitals and posterior dilatation of maxillary, covered with 

 scales, as well as the cheeks and opercular api:)aratus. Suborbital and preopercle serrated. 

 Opercle provided with a spine. Branchiostegals six or &even in number. Card-like teeth on 

 the jaws ; velvet-like teeth disposed upon a transverse band in front of the vomer and upon a nar- 

 row band along the palatines, sometimes only towards the anterior extremity of the latter bones. 



Stn. Percichthijs, Grd. Proc. Acad. Nat. Sc. Philad. VII, 1854, 197. 



Ob.s. This genus, closely allied to Ferca, is to be distinguished from it by the shape of the 

 snout and the structure of the mouth; the presence of small scales on the top of the head, on 

 the suborbital bones and (upper) maxillary ; the position of the ventral fins, and by the pres- 

 ence of three spiny rays, instead of two, at the anterior margin of the anal fin. Moreover, the 

 head, as a whole, has soniething of a sciasnoid touch about it. 



Perca truclia, of Cuv. and Val.* which, according to M. d'Orbigny, is an inhabitant of 

 the Kio Negro of Patagonia, is a species of this genus. 



I am led to consider Perca ciliata, K. and V. H., from the island of Java, Perca marginata, 

 Cuv. and Val., brought to France from the austral hemisphere by the navigator Peron, and 

 Perca trutta, Cuv. and Val., from Cook's straight (New Zealand), as properly referable to the 

 genus Percichthys. 



Should this be true, the hitherto cosmopolite genus Perca would thus be restricted to the 

 boreal hemisphere; the analogous species of the austral hemisphere constituting an allied genus 

 or several allied genera, since one of the species of this group has led us to the establishment of 

 another genus equally distinct from both Perca and Peroichthys. 



Perca lavis, Jen.,t an inhabitant of the Piio Santa Crux, Patagonia, belongs also to the 

 genus Percichthys, being closely allied to P. truclia, if at all distinct from it. 



The following is the formula of its fins and branchiostegals: 



Br. 7; I).9 — l/ll; A. s/O; C. 17; P. 15; V. 1/5. 



Again, Perca truclia of Cjiv. and Val. is not identical with the Perca truclia of the "Historia 

 de Chile." The latter we propose to call Percichlliys cMlcnslt. The distinctive marks between 



' HlHtoire Naturelle des Poissons. Tome IX, 1833, 429. 

 t Zool. uf Beadle, IV. Fisb. 1812, I, PI. i. 



