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ACANTHOPTERYGII, — PERCAD.E. 
Genus Perca. (Linn,) 
The distinctive characters of the Perches pro- 
per are two dorsal fins quite separated, of which 
the fore one possesses only spinous rays, the 
hinder only flexible or soft ones. The tongue is 
smooth ; the mouth is armed with teeth, situated 
in both jaws, in front of the vomer or middle 
HEAD OF PERCH. 
ridge of the palate, and on the bones of the 
palate itself ; the fore gill-flap {preoperculum) is 
notched below, and has its hind edge cut into 
small teeth like those of a saw ; the gill-cover 
{operculum) is bony, and terminates in a flattened 
spine pointing backwards. The gill-arches are 
