46 FISH CULTURE. 



result from the spreading of it to other and hitherto 

 sound eggs. The best way is to sacrifice at once all 

 that have come under its influence, or you can re- 

 move them to some spare tray below the other eggs, 

 where they may take their chance safely. So that 

 one of the most necessary duties to perform diurnally, 

 where the ova is exposed to view, is to remove, with 

 a pair of forceps, those which are bad. In this 

 respect, the small squillidae or hopper, of the fresh 

 water, and insects of a like kind, are said to be useful 

 as scavengers, and their attacks on the live ova not 

 to be feared ; x although the amount of stream need 

 be but small. I do not of course presume to say 

 that a fair amount of stream is not preferable in 



1 Of this I do not feel so certain. A few days since, while out 

 fishing, I picked up a mussel but recently dead. On looking into it 

 I noted a dark mass of something, which on closer inspection 

 proved to be a vast collection of these little hoppers, to the extent 

 of hundreds. The shell was almost full of them, and they had 

 eaten holes larger than themselves already in the mussel, which had 

 not been long dead, the flesh being quite fresh and free from smell 

 or taint. Indeed, I am quite inclined to think that they had 

 actually killed it. Still, I must allow that in the Christian-spring 

 rill mentioned above these insects abounded to profusion ; and 

 although we did our best to keep them out of the boxes, numbers 

 of them did get in. Yet I do not think they did any harm to the 

 ova. If they did, it was not to any great extent. If it be necessary 

 to keep them out, nothing but the finest wire sieveing will do it, 

 where they at all abound. 



