56 BRITISH FISH AND FISHERIES. 



skeleton are firm and hard, though less so than 

 in quadrupeds or birds. In the cartilaginous 

 fishes, such as the shark, the skates or rays, the 

 lampreys, etc., the bones of the skeleton are 

 never completely ossified ; they permanently 

 exist in a state of tough firm cartilage. 



These two sections are resolved into several 

 orders, each order comprising numerous fami- 

 lies, composed of genera, in near relationship 

 with each other. The first order of the osseous 

 series is termed the acanthopterygious, (Acati- 

 thopterygii,) which, in plain English, means 

 "fishes with the fin-rays of their dorsal fin 

 spinous, or, at least, mostly spinous." Of this 

 order the perch family {Percidce) is very con- 

 spicuous. 



The perch {Perca fluviatilis) is too well 

 known to need any detailed description. It is 

 distributed over the whole of Europe, living in 

 rivers, lakes, and lai'ge ponds ; it is remarkable 

 for beauty, and the sharpness of the spines of 

 the first dorsal fin, by which latter the hands 

 of incautious or inexperienced fishers are often 

 severely lacerated. These spines serve as very 

 efficient defensive weapons, so that a good-sized 

 perch need not fear even the ferocious pike. 

 The perch is gregarious in its habits, and 

 frequents the still and quiet parts of rivers, 



