66 LECTURE VIII. 



Among the Thoracic Fishes rank all the kinds 

 of Perches, forming the Linnaean genus Perca. 

 They have sharp teeth, scaly and serrated gill- 

 covers, and a back-fin with the fore-part furnished 

 with spiny rays, and the back part with soft' ones; 

 and the scales in most species are hard and rough. 

 The common Perch is an elegant fish, of an olive 

 brown, marked by.five or six dusky transverse bars, 

 and is found in most parts of Europe. 



Very strongly allied to the genus Perca are 

 the several lately instituted genera of Holocentrus 

 Scitena and some others. 



The Fishes of the Mackrel tribe belong to a 

 genus called Scomber, and are distinguished by 

 their oblong body, furnished above and below the 

 back-part near the tail, with several small or spu- 

 rious fins : in some species also the lateral line OP 

 middle longitudinal division of the Fish is fur- 

 nished with a series of strong and broad scales. 

 The common Mackrel is universally known, and 

 is certainly one of the most beautiful of the Eu^ 

 ropean Fishes. Its celebrated migrations, so well 

 detailed in the entertaining work of Mr. Pennant, 

 begin now to be greatly called in question, and it 

 is rather supposed that the glittering myriads 



