372 



TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



groups of the plankton per haul of the standard net (coarse 

 and fine nets together forming one standard "double 

 haul "). The maxima are printed in heavier type. 



1913. 



Double 

 hauls. 



Average 

 catch. 



Diatoms. 



Dinoflag- 

 ellates. 



Copepoda. 



Copepod. 

 nauplii. 



January 



February . . . 

 March 



8 

 7 

 8 

 8 

 9 

 8 

 10 

 8 

 9 

 7' 

 7 

 6 



3-6 



3-6 



6-7 



27-3 



401 



33-8 



25-2 



7-3 



8-4 



3-9 



40 



2-8 



23,585 



59,510 



372,575 



3,007,444 



26,927,403 



3,010,827 



3,279,375 



94,110 



187,578 



10,170 



92,031 



36,697 



657 



2,767 



6,157 



5,541 



30,422 



104,131 



145,385 



69,736 



6,872 



563 



5,573 



6,015 



4,011 



3,877 



5,723 



8,222 



11,011 



51,851 



54,117 



29,751 



39,163 



19,961 



30,697 



8,283 



1,144 



4,117 



24,162 



April 



23,894 



May 



17,189 



June 



July 



34,150 

 27,370 



August 



September ... 



October 



November ... 

 December . . . 



25,405 

 25,089 

 12,443 

 12,284 

 2,552 



From this table we see that the spring maximum was 

 in May, as it was in 1911, but the increase began earlier, 

 and continued later than in that year. The actual largest 

 haul was 722 c.c. on May 16th. In 1912, we noticed that 

 the maximum was spread over a considerable length of 

 time, namely, from March to June, with the highest point 

 in June; this year it is of the same duration (four months), 

 but is from April to July, agreeing in this respect with 

 1910. The September maximum is much lower than in 

 any previous recorded year, the largest catch being 

 152 c.c. on the 18th, and the average for the month only 

 84 c.c, as against 23*4 c.c, 153, 15'6, and 12*1 in the 

 last four years. 



It will be noticed on the table that the maximum of 

 the Dinoflagellata and the Copepoda (July) occur much 

 later than that of the Diatoms (May) — the Dinoflagellata 

 being distinctly later than usual. 



