| Ds Baboye & bir 
BY CHARLES GIRARD. 
FAMILY OF PERCIDE. 
Genus PERCICHTHYS, Girard. z 
Gen. cuar. Body oblong or elongated, compressed, covered with scales of medium develop- 
ment, finely 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 surface of head, suborbitals and posterior dilatation of maxillary, covered with 
scales, as well as the cheeks and opercular apparatus. Suborbital and preopercle serrated. 
Opercle provided with a spine. Branchiostegals six or seven 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. 
Syn. Percichthys, Grp. Proc. Acad. Nat. Sc. Philad. VII, 1854, 197. < 
Ors. This genus, closely allied to Perca, 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 something of a sciznoid touch about it. 
Perca trucha, of Cuv. and Val.* which, according to M. d’Orbigny, is an inhabitant of 
the Rio Negro of Patagonia, is a species of this genus. 
Tam led to consider Perca ciliata, K. and Y. H., from the island of Java, Perca marginata, 
Cuy. and Val., brought to France from the austral hemisphere by the navigator Péron, 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 Percichthys. 
Perca levis, Jen.,{ an inhabitant of the Rio Santa Crux, Patagonia, belongs also to the 
genus Percichthys, being closely allied to P. trucha, if at all distinct from it. 
The following is the formula of its fins and branchiostegals: 
Br. 7; D.9—1/11; A. 3/9; C. 17; P. 15; V. 1/5. 
Again, Perca trucha of Cuy. and Val. is not identical with the Perca trucha of the ‘Historia 
de Chile.’’ The latter we propose to call Percichthys chilensis. The distinctive marks between 
* Histoire Naturelle des Poissons. Tome IX, 1833, 429. 
t Zool. of Beagle, IV. Fish. 1842, TI, Pl. i. 
