274 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



weather. The lowest records for any month are 

 14 samples in May, in July and in October, and the 

 highest are 32 in February and 33 in March. The average 

 per month is thus nearly 20 hauls. 



The coarse and the fine net obtained very different 

 samples, both quantitatively and qualitatively. For 

 example, as a rule the coarse net caught more adult 

 Copepods, and the fine net more of the Nauplii. Conse- 

 quently, by adding the two hauls together we get what 

 may be regarded as a representative sample of the 

 plankton obtainable in one traverse of the bay. In 

 January there were 11 hauls of the coarse net ranging 

 from 1 to 4 c.c. in quantity, and 11 hauls of the fine net 

 ranging from 01 to 1*4 c.c. ; and if each pair of hauls be 

 treated as one, the range for the month is 1*2 to 5*4 c.c, 

 and the average double-catch is 2*2 c.c. In the following 

 table the numbers of the Diatoms and other leading 

 groups of organisms have been treated in a similar 

 manner : — 





Double 



Average 



Diatoms. 



Di no flag- 



Cope- 



Copepod 





hauls. 



Catch. 





ellates. 



poda. 



Nauplii. 



Jan. . . . 



11 



2*2 



12,062 



486 



5,608 



1.766 



Feb. ... 



16 



1-76 



23,998 



178 



1,708 



658 



Mar. ... 



16 



2-5 



77,423 



273 



1,168 



944 



Apr ... 



8 



14-08 



1,961,333 



8.171 



1,269 



4,498 



May ... 



7 



24-07 



1,166,537 



30,95'/ 



7,701 



18,141 



June ... 



9 



22-9 



2,612,156 



25,343 



10,644 



20,867 



Julv ... 



7 



10-05 



153.616 



9,393 



16,624 



23,969 



Aug. ... 



7 



6-84 



8,319 



3,440 



20,078 



14,893 



Sept. ... 



7 



12-15 



574,571 



814 



14,442 



19,786 



Oct, ... 



7 



5-97 



27,914 



289 



28,935 



15,879 



Nov. ... 



8 



3-73 



79,244 



3.099 



7,190 



4,778 



Dec. ... 



9 



40 



37,626 



2,133 



8,258 



4,153 



This shows that the maximum catch, so far as 

 volume is concerned, was in May; that the Diatoms have 

 an extended maximum from April to June, with its 

 climax at the end ; that the Dinoflagellates are most 



