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THE ROYAL SOCIETY OF CANADA 



Table II. 

 CopEPODs OF Stage V in Exuviation to Stage VI. 



The freshly gathered plankton was brought from the outside to 

 the laboratory in quart thermos flasks. The material was then 

 decanted into a glass jar, active copepods picked out with a glass tube 

 and transferred to a litre flask containing filtered sea-water sterilized 

 by heating to 70°C. The most successful experiment was started on 

 July 14th from material conveyed to the laboratory in a thermos 

 flask on the previous day. The air temperature in the laboratory at 

 9 a.m. was 19°C. The half-filled litre flask was loosely corked and 

 placed in an ice-house near the laboratory, with a fairly constant 

 temperature of 10°C. The Copepods remained active, without addi- 

 tion to diatom food, until August 28th, when the experiment was 

 discontinued. See Table II. 



Number 15, table II, proves that those copepods of Stage V 

 with 2 Se on the Ri do not always exuviate to males (Fig. 28). Those 

 that were undoubtedly exuviating to females as shown by the seg- 

 mentation and the enlagrement of the first segment, of the urosome, 

 (Figs. 1, 2, 25) and the large number of teeth on Bl of p5, showed no 

 peculiarities which might distinguish their sex in stage V, nor did 

 those exuviating to males as shown by the segmentation of the uro- 



