60 



ACANTHOPTERYGII. — PERCAD^. 



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 

 spiine pointing backwards. The gill-arches are 



