PERCHES WITH A SINGLE DORSAL FIN. 



WE now come to the second great division of 

 the Percoid Fishes, characterized and known at 

 first sight by the simple character of a single 

 dorsal fin, no separation appearing between the 

 spiny and softly rayed part. The sub-divisions, 

 it will be seen, are taken from the opercle, pre- 

 opercle, teeth, and jaws. The first genus is 

 Serranus, containing a numerous series of species, 

 almost all of them remarkable for the beauty of 

 their tints and singularity of marking. Cuvier has 

 separated them into three sections : the first have 

 the jaws naked, and they are of a small size ; the 

 second are fish of greater size, and have the under 

 jaw scaled ; and the third, of middling size and 

 lively colours, have the head and jaws covered 

 with scales similar to those of the body. The first 

 we shall notice is a beautiful fish from the Medi- 

 terranean Seas, the 



