132 ACANTHOPTERYGII. PERCH FAMILY. 



vier, is known of its habits, except that at Nice it 

 approaches the shore in April and May, when it 

 deposits its spawn. 



Genus IV. Acerina. (Sp. 5.) A. vulgaris. The 

 Ruffe or Pope (PI. II.), is the only representative of 

 this genus found in Britain. It is a river fish, " The 

 Smaller River Perch" of Gesner, and the " Small 

 Perch" of Bloch. From these statements it will 

 be inferred that it is closely allied to the Common 

 Perch; from which it is distinguished chiefly by 

 having a single dorsal fin, the rays of which are 

 spinous in the anterior part, and flexible in the 

 posterior. It appears to have been first described 

 by Dr. Caius, who detected it in the Yare, near 

 Norwich. Mr. Yarrell states that it is common 

 in all the canals and rivers in England, particu- 

 larly the Thames, Isis, and Cam : it is unknown 

 in Scotland; and also, as stated, in Spain, Italy, 

 and Greece : it is found, again, in the colder parts 

 of Europe, and is common throughout France. It 

 is more slender than the Perch, and seldom ex- 

 ceeds six or seven inches in length. The colour of 

 the upper parts of the body is light olive brown, 

 passing into yellowish-brown on the flanks, and 

 into white on the abdomen : the lateral line is 

 prominent, and strongly marked. Its food is the 

 same as that of the Common Perch, and, like it, it 

 is very voracious, and fearless in taking a bait ; its 

 flesh is considered excellent : it spawns in April 

 among roots and rushes. According to Mr. Pen- 

 nant, it is gregarious, assembling in large shoals, 



