CYTOLOGY AND GENETICS 341 



character at either end of the lake. In the north basin the quantity was 

 comparatively small, and consisted for the most part of Crustacea (Cladocera 

 and Copepoda), whereas in the south basin the quantity was large, and 

 consisted for the most part of phytoplankton throughout the period observed. 

 This was due to the abundance of only a few species of Myxophyceae and 

 Diatomaceae. 



This abnormally abundant production of phytoplankton in the south 

 basin continued without diminution all through the winter, and is apparently 

 due to drainage effluents from towns and villages discharging into this 

 portion of the lake. A similarly large production of marine winter phyto- 

 plankton occurs in the inlets on the west coast of Vancouver Island where 

 fish reduction factories discharge their waste. In Windermere the zoo- 

 plankton does not seem to be directly affected by this condition except in so 

 far as the phytoplankton may afford a more abundant food supply ; but 

 further study of the conditions obtaining on the two basins may have a 

 pertinent bearing on the problems of water supply and the practicability 

 of artificially increasing human food supplies. 



CYTOLOGY AND GENETICS. 



Report of Co-ordinating Committee for Cytology and Genetics (Prof. Dame 

 Helen Gwynne-Vaughan, G.B.E., Chairman ; Dr. D. G. Catche- 

 siDE, Secretary ; Prof. F. T. Brooks, F.R.S., Prof. F. A. E. Crew, 

 Dr. C. D. Darlington, Prof. R. A. Fisher, F.R.S., Mr. E. B. Ford, 

 Prof. R. R. Gates, F.R.S., Dr. C. Gordon, Dr. J. Hammond, Dr. 

 J. S. Huxley, F.R.S., Dr. T. J. Jenkin, Mr. W. J. C. Lawrence, 

 Dr. F. W. Sansome, Dr. W. B. Turrill, Dr. C. H. Waddington, 

 Dr. D. Wrinch). 



The Committee have continued to assist and advise Organising Committees 

 and Recorders in arranging for joint sessions and other means for promoting 

 closer co-operation between cytology and genetics and other fields of biology. 



It was thought that the bearing of recent cytological and genetical dis- 

 coveries on other aspects of the old problem of the Mechanism of Evolution 

 was imperfectly understood by many biologists. The Organising Com- 

 mittees of Sections D and K were approached with the suggestion that a 

 joint symposium occupying a morning and afternoon session should be 

 devoted to this subject. The proposal was approved, and a number of 

 papers dealing with various phases of the problem have been arranged. 



The Organising Committee of Section M were unable to find space in 

 their programme for a discussion of Genetics in Relation to Agriculture. 

 However, they sought the Committee's advice in arranging for genetical 

 contributions to their symposia on Crop and Stock problems respectively. 



The Committee have also felt that a useful service would be rendered to 

 workers in other biological fields by the presentation of demonstrations. 

 They have organised an exhibition illustrating the principles of the Genetics 

 of Colour in Animals and Plants, demonstrating wherever possible the 

 chemistry of the pigments and colour differences concerned. A descriptive 

 brochure is in course of preparation. 



