184 TRANSACTIONS LIVEEPOOL BIOLOGICAL SOCIETY. 



but up to the end of March, by which time a considerable 

 number of larvae had been liberated at sea, there was still no 

 great abundance of phyto-plankton. It is possible, therefore, 

 that the year-class 1920 may be poorly represented in future 

 fisheries, if the plaice larvae hatched out naturally in the sea 

 were on the average as early as in our pond and assuming that 

 they were dependent upon the Diatoms* for food. 



NOTE. — In concluding this Keport, I desire to express 

 the hope that during the coming year I may be able to 

 undertake a re-consideration of the accumulated data of these 

 14 years (1907-20 inch) of plankton work in the Irish sea, and to 

 offer in some future report a general summary of those results 

 that seem to be sufficiently established. — W. A. Herdman. 



* It is possible that in addition to smaller organisms such as Flagellates 

 they may also make use of various minute invertebrate embryos and larvae 

 such as those of some Echinoderms, worms and Molluscs, and of Oikopleura 

 which is usually fairly abundant in the plankton at the time. 



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