304 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



Plankton. 



It was shown in last year's Keport that one of the most 

 important things the Biologist can do to add to our know- 

 ledge of life in the sea, with a practical view to the 

 explanation of the movements and distribution of fish, is 

 to make a systematic survey of the microscopic floating 

 and drifting life of the sea, and its relation on the one 

 hand to the physical conditions at the time (especially 

 the temperature and salinity of the water), and on the 

 other to the food materials found in the stomachs of the 

 fish. 



We have continued our efforts during the past year to 

 contribute our share towards a knowledge of 

 this " plankton" life of the sea round the 

 British coasts. At some considerable expense 

 we purchased a small hand pump, fitted on a 

 stand for convenience of work on deck, and 

 20 fathoms of india-rubber hose-pipe for lower- 

 ing to the bottom. This apparatus 

 was used on several occasions early 

 in the year, with rather disappointing 

 results. It may be the more exact 

 method in so far that it only gives 

 organisms from the definite depth to 

 which the end of the hose-pipe is 

 lowered, while an ordinary open tow- 

 net, lowered to the depth in question 

 and raised again, may show some 

 small admixture of organisms from 

 the water above ; but, on the other 

 hand, the open tow-net catches far 

 more material, and therefore gives 

 a more complete knowledge of the 



fauna. 



A Tow-Net. 



