SEA-FISHERIES LABORATORY. 197 



AN INTENSIVE STUDY OF THE MARINE 

 PLANKTON AROFND THE SOUTH END OF 

 THE ISLE OF MAN.—PAET Y. 



By W. A. Herdman, F.R.S.. and Andrew SroTT, A.L.S. 



METHODS. 



The work was carried on during 1911 on the same 

 lines as in ])revious years. Mr. W. Riddell ajgain gave 

 most efficient lielp at sea, in the observations taken from 

 the yacht; Mr. Chadwick and Mr. T. N. Cregeen, of the 

 Port Erin Biological Station, collected the samples from 

 Port Erin Bay throughout the year; the two authors 

 divided the rest of the work as before; and Miss H. M. 

 Lewis, in the Zoological Department of the University 

 of Liverpool, devoted a great deal of time and trouble to 

 compiling the statistics, tables, curves and diagrams 

 from which this paper is written. 



The work at sea from the steam-yacht '' Runa " was 

 carried on for some weeks in April, and again in the later 

 summer (August and September), usually the two most 

 important times of planktonic change. During the rest 

 of the year, statistical weekly gatherings were taken for 

 us in Port Erin Bay, in accordance with a uniform plan, 

 by the staff of the Biological Station. 



We do not propose this year to make such a detailed 

 statement of the results as we have done for previous 

 years, but rather to give conclusions and comparisons, 

 and to pick out for remark any matters that seem new or 

 unusual. Consequently we would refer readers who are 

 interested in a fuller discussion of any points we have 

 already dealt with to the preceding four parts of this 

 work. (See Reports for 1907-1910.) 



