SEA-FISHERIES LABORATORY. 299 



suddenly in an area where previously unknown. It is 

 possible that the " sudden appearance " which leads to 

 the identification is due to a local increase in numbers 

 permitted by some change in the environment. 



Outside the bay, Microcalanus behaves pretty well 

 in agreement with Sars' description of it as a mid-water 

 form. It appears in the open-sea nets 68 times in the 

 three years. In 40 of these, or almost 60 per cent., it 

 was present only in the vertical nets ; in only 15, or 

 22 per cent., does it appear in the surface nets; and in 

 about 25 per cent, in the " weight " net. Thus it is 

 evident that Microcalanus is at least not a surface form. 

 Paulsen finds it in quantity in deep hauls to the North of 

 Iceland. 



Cirripedia. 



The Balanus larvse are rather interesting. The Nauplii 

 (fig. 10, p. 319) begin on February 6th y reach 3,000 on 

 the 24th, 12,000 on March 31st and 10,000 on April 13th; 

 decline to 1,100 on April 22nd, to 150 on May 12th, and 

 disappear at the end of May. Those of the Cypris stage 

 (fig. 11) appear first on April 13th, reach 900 on 

 May 12th, and disappear at the end of June. The 

 Nauplii are at their climax in early April, the Cypris in 

 the middle of May. 



In times of first appearance (e.g., Nauplii on 

 February 22nd in '07, February 13th in '08, February 6th 

 in '09) and of maxima these figures agree substantially 

 with those of the two previous years. 



Cladocera. 



The constancy of this group is remarkable — Evadne 

 ranging from March or April to the end of August or 

 September in each of the three years, and Podon from the 



