Class IV. COMMON PERCH. 347 



dom grow to a large size : we once heard of 

 one that was taken in the Serpentine river, 

 Hyde-Park, that weighed nine pounds, but that 

 is very uncommon. 



The body is deep ; the scales very rough ; Descrip- 

 the back much arched ; the side-line near the TI0N * 

 back ; the irides golden ; the teeth small, dis- 

 posed in the jaws and on the roof of the mouth ; 

 the edges of the covers of the gills serrated ; on 

 the lower end of the largest is a sharp spine. 

 The first dorsal fin consists of fourteen strong 

 spiny rays ; the second of sixteen soft ones ; 

 the pectoral fins are transparent, and consist of 

 fourteen rays ; the ventral of six ; the anal of 

 eleven ; the tail is a little forked. The colors 

 are beautiful ; the back and part of the sides 

 being of a deep green, marked with five broad 

 black bars pointing downwards; the belly is 

 white, tinged with red ; the ventral fins are of a 

 rich scarlet ; the anal fins and tail of the same 

 color, but rather paler. 



In a lake called Llyn Rathtyn, in Meireo- Crooked 

 netkshire, is a very singular variety of perch : 

 the back is quite hunched, and the lower part 

 of the back bone, next the tail, strangely dis- 

 torted : in color, and in other respects, it resem- 

 bles the common kind, which is as numerous 

 in the lake as these deformed fish. They are 



