238 Transportation of Fish from 



have loaches, and some other small fish ; and while, formerly, there 

 were none of the former two, the water is now absolutely swarm- 

 ing with them. Thus also, apparently, the eels have multiplied ; 

 as it is now easy to take a cartload at once, where formerly a 

 dozen or two was a large capture. I have thus also more dis- 

 tinctly ascertained, and to the satisfaction of Cuvier, who had 

 been unwilling to admit it, that there are two species of fresh^ 

 water eel, distinguished by the comparative acuteness and breadth 

 of the nose. 



I have lastly to add an observation inadvertently omitted in the 

 former communication, which may be used as an & priori argu- 

 ment for the possibility of this transplantation. It is, that oxy- 

 gen is much more easily disengaged from fresh than from salt 

 water. Consequently, the act of respiration ought to be easier in 

 the former than in the latter ; and therefore it is not to be pre- 

 sumed, as it has been, that sea-fish cannot respire fresh water. 



As I have given the shad without its Linnaean name, I think it 

 right to add, that our shad is yet unnamed ; because the Clupea 

 Alosa is the Alose of the French, common in the Seine and on the 

 coast of Normandy ; a fish as good as our own shad is detestable, 

 and a decidedly different species of this troublesome and ill un- 

 derstood genus. If I have given the vulgar term rock-fish, it is 

 because I wish to reject the term wrasse, for the present, as it stands 

 for a species ; whereas the whole of this genus (labrus) is still in 

 extxame confusion, and in one, which I hope to aid in rectifying, 

 with the assistance of Cuvier 's materials and our own species. 



I am yours, &c., J. MAC CULLOCH, 



Prospectus of a Plan for Preserving and Rearing Fish for the 

 London Market. 



From various observations and experiments, of which evidence 

 is subjoined, it has been found that sea-fish will live and thrive, 

 and also breed, in ponds or enclosures ; and, with regard to many, 

 it also appears that it is indifferent whether the water is salt, or 

 fresh, or brackish, or alternately fresh and salt. 



It is also found that they may be fed in such enclosures, if ne- 



