FISHES AND FISHING. 77 



Gentlemen who have the means at command, could 

 easily ascertain the possibility of this suggestion 

 being carried out, and could watch the effect upon 

 the fish produced; supposing that the same law 

 obtains in respect to fish as to hybrids of the terrence 

 animals, and that hybrid fish have no power of pro 

 ducing a progeny (a question of easy solution), there 

 would be little difficulty in annually stocking the 

 Thames and other rivers with a valuable hybrid, 

 thereby most materially benefitting the community 

 in many parts of the world, as well as in these 

 kingdoms. 



A curious illustration of the physiology of breed 

 ing is to be found in the little fish called the ruff, or 

 pope, which is no doubt a hybrid, for it is marked 

 like a gudgeon, but has the form of the perch, is, like 

 the latter, gregarious, a fish of prey, erects his dorsal 

 fin as a defence, and is probably produced from the 

 ova of a gudgeon vivified by the milt of a perch. 

 Now this at first view may appear very extraordi 

 nary, seeing that the perch are constantly preying 

 upon gudgeons, and cannot be supposed to form any 

 friendly connexion, but it may be easily accounted 

 for ; thus, the latter with ova at maturity, in endea 

 vouring to escape from the former, might, and most 

 likely do, from the exertion, exude some of the ova, 

 and the former from the same cause probably excrete 



