SEA-FISHERIES LABORATORY. 



293 



[1914. 



Ceratium 

 tripos. 



Peridinium • 

 spp. 



"1914. 



Ceratium 

 tripos. 



Peridinium 

 spp. 



January 



February 



March 



2,102 

 1,734 

 3,835 

 7,993 

 12,947 

 5,744 



2 







84 



3,519 



17,322 



8,027 



Julv 



3,987 



1,003 



1,335 



19,522 



21,917 



15,571 



1,582 



August 



September ... 



October 



November ... 

 December . . . 



1,422 

 20 



April 







May 



333 



June 











This year agrees with 1912 in having the spring 

 maximum of both groups in May, but the distribution in 

 1914 was more regular than in the former year. It will 

 be seen from the figures given above that the curve of 

 the monthly averages is very regular indeed, rising in 

 the case of Ceratium from February to May, then falling 

 to a minimum in August and rising again to the autumn 

 (and this year higher) maximum in November. A 

 similar regularity is to be noticed in the case of 

 Peridinium. The actual maximal hauls are, for 

 Ceratium, 30,000 on May 12th and 32,000 on October 

 15th, and, for Peridinium, 48,000 on May 14th, and 

 2,000 on November 3rd, this last figure being the sole 

 record we have for the last three months of the year, 

 and evidently, therefore, quite an exceptional occurrence. 



Noctiluca. 



Noctiluca miliaris was rather more abundant in 1914 

 than in the previous year, and the maximum appears to 

 have been in May (10,200 on the 21st, 10,800 on the 28th). 

 This is unlike 1912, when we stated that, "on the whole, 

 Noctiluca seems to be least plentiful in spring and early 

 summer, and to become more abundant in autumn." Last 

 year we recorded as characteristic "the constant presence 

 of the organism in small quantity." But on the whole, 

 as we then pointed out, it is more usual for " Noctiluca to 

 be either totally absent, or present in great profusion." 



