SECTIONAL TRANSACTIONS.— D. 337 



is found between the number of herrings caught and the number of the 

 copepod Calanus, an important food organism in the plankton ; a negative 

 correlation is found with the pteropod Limacina. Other negative correla- 

 tions are indicated but not yet established. Reference was made to 

 the beginning of an experiment in charting the plankton on a broad scale 

 by means of continuous plankton recorders on steamship lines across the 

 North Sea, with a view to forecasting the conditions on the fishing grounds 

 later in seasons. The work here described has been carried out in the 

 Department of Oceanography at the University College of Hull, with the 

 assistance of Dr. G. T. D. Henderson and Mr. C. E. Lucas, members of 

 the research staff. An attempt was made to estimate the commercial 

 value to the industry of the results so far obtained with the Plankton 

 Indicator. 



Mr. A. C. Stephen. — The faunistic divisions of the floor of the North Sea. 

 (At the Rialto, Fishergate, by the kind permission of the proprietor.) 



Of the various groups of molluscs which occur the Lamellibranchs are 

 by far the most important numerically, and by the major variations in their 

 density the northern North Sea may be divided into three distinct zones : 

 (a) the coastal zone occupying the narrow strip within the 20-fm. line ; 

 (6) the wide zone of low density occupying much of the area beyond ; and 

 (c) the north-eastern portion of the North Sea, where the density is again high, 

 but where all the forms are dwarfed. The fauna of the southern North Sea, 

 below the 30-fm. line, is similar to that of the Scottish coastal zone, so 

 that the division into three zones still holds good. The echinoderms follow 

 much the same course. 



A number of workers have accepted the ' community ' concept, but the 

 results from Scottish waters show that, for the North Sea at least, a division 

 by zones provides a better method. Species occur in certain zones, but 

 spat may fall in any part of the zone, causing great fluctuations in density 

 of any species. A species may be abundant in one part of the zone at one 

 period and absent at the next. These fluctuations have an economic aspect. 



Afternoon. 



Joint Discussion with Section H (Anthropology) on The Primates and 

 Early Man (Dr. C. Tate Regan, F.R.S. ; Dr. A. B. Appleton ; 

 Dr. S. Zuckerman). 



Tuesday, September 6. 



Symposium on Applied Helminthology : — 



Prof. R. T. Leiper. — General introduction and the applications of 

 helminthology to medicine. 



Dr. T. W. M. Cameron. — Applications to veterinary medicine. 



Dr. Marjorie J . Triffitt. — Applications to agriculture and horticulture . 



Dr. T. Southwell. — Applications to fisheries. 



Mr, F. J. Brown. — Zoological aspects. 



