ORSERVATIONS ON THE PLANKTON OF LOOE POOL. 333 



venieut for reference. To this I have appended a list of the 

 various species mentioned. 



Methods of Collecting. 



All the samples of tow-net gatherings recorded in this paper 

 were made from rowing-boats. After two preliminary visits, I 

 decided on the following plan of work. The visits to this lake 

 were to be made once a month. On each occasion three 

 gatherings were always to be made— one on the surface, another 

 just clear of the bottom, and a third mid- way between these two. 

 The surface gathering was always made well to leeward, the 

 object being to secure all the surface forms blown thither by the 

 wmd. The mid-water and bottom gatherings were invariably 

 made in the same place, the deepest spot in the pool, which I 

 have indicated in the accompanying ]3lan by two asterisks. 



The tow-nets were made of silk bolting-cloth. The mouth 

 of each net was twelve inches in diameter. No special contrivance 

 was used to exclude specimens from being captured during the 

 passage of the net to and from the surface. The net and the tin 

 receiver at the end were always well raised between two succes- 

 sive hauls. 



The greater part of each gathering was preserved on the 

 spot with Formalin. About a third of each gathering was taken 

 home untouched for further microscopical examination, and in a 

 living condition. 



The temperatures were all taken with a deep-sea thermometer 

 made by Messrs. Negretti and Zambra, mounted in a Scottish 

 frame. 



