CHAPTER XII. 



THE fishes about to be described are, with one exception 

 (the Lampreys), to be found among the sub-class TELEOSTEI 

 or BONY FISHES. That is, the skeleton is ossified ; the 

 vertebrae (spinal column) completely formed ; the branchiae 

 (gills) free, and protected by a bony gill-cover. 



This great sub-class is again divided into six Orders ; 

 each order subdivided into families, genera, and species. 



THE PERCH. 



The first Order is that of the ACANTHOPTERYGII (from 

 two Greek words, acantha, a thorn or prickle, and pteros, 

 a fin), distinguished by having a portion of the dorsal, 

 anal, and ventral fins not articulated, forming spines ; the 

 air-bladder, when present, being completely closed and 

 having no air duct. To this order 



The family Perddce (the Perches) belong. Gunther 

 says : " In the Perddce the scales extend rarely over the 

 vertical fins ; the lateral line is generally present, and con- 

 tinuous from the head to the caudal fin. All the teeth are 

 simple and conical. There are no barbels, and no bony 

 stay to the preoperculum." 



The FRESH-WATER PERCH (Perca fluviatilis) is found in a 

 great many of the rivers, lakes, and ponds in England. It 

 is more rare in Scotland. Yarrell, however, says that it 

 is found in some of the lochs of North Britain, and it is 

 pretty generally distributed in nearly all the fresh-waters 

 of Ireland. 



Day says the name of the fish is of Greek origin, signi- 

 fying "dark colour," which probably refers to the dark 

 bands across the body ; " while this nomenclature has been 



193 N 



