D. J. SCOURFIELD ON THE ENTOMOSTRACA OF NORTH WALES. 141 



does not sound very formidable, it must be remembered that from 

 the point of view of individuals these forms far outweigh all the 

 others put together. It is the capture of these pelagic animals, 

 too, which constitutes the chief peculiarity of "pond-hunting" 

 in North Wales, and this leads to the consideration of the second 

 point I wish to mention. It is quite useless to think that, with a 

 net attached to a stick, worked by hand from the shore, any idea 

 of the pelagic fauna of a lake can be obtained. The only really 

 reliable method of getting the creatures belonging to this group is 

 by the use of a boat. From this the net can be used not only at 

 the surface, but by means of a line and plummet can also be lowered 

 to various depths, or dragged along the bottom. It is absolutely 

 necessary to be able to use the net in these various ways, for it 

 often happens that while the surface is almost devoid of life, a rich 

 collection of pelagic forms may be secured at a considerable depth. 

 But boats are only to be had on a few lakes, and if we want to 

 study the pelagic fauna in the others some different means of 

 collection must be adopted. 



Under favourable conditions some specimens of this fauna can 

 usually be obtained by the simple means of attaching the net to a 

 line and throwing it out as far as possible. Of course the net must 

 be weighted in some way, and I found it a good plan to substitute 

 for the usual glass tube at the end of the net a small cylindrical 

 tin into which some molten lead had been run. With the majority 

 of the higher lakes this method of throwing out the net is 

 perhaps the only one open to a person who, like myself, simply 

 does his collecting incidentally during a holiday. In North Wales 

 however, I found a most fatal objection to this method to be that 

 very commonly, even in lakes known to be of considerable depth, 

 there was a margin of comparatively shallow water, extending well 

 beyond the point to which the net could be thrown, and thus effec- 

 tually preventing the examination of the deeper water. Several 

 more complicated methods of collecting, by means of floats etc. 

 have been proposed for this kind of work, and have, I believe, 

 proved fairly successful. At some future time I hope to be able to 

 give some of these a trial, at least in the more accessible lakes. 

 In the meantime if anyone interested should be willing to continue 

 this subject of the Entomostraca of North Wales, in any of its 

 branches, I shall be only too glad to do anything I can to help in 

 the work. 



Jouen. Q. M. C, Series II., No. 37. 10 



