276 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



The spring phyto-plankton maximum in '09 does not 

 show any great abundance of an unusual organism, such 

 as the immense swarm of Thalassiosira nordenskioldii that 

 invaded the Irish Sea in '07. 



l<m C/WTVC WUAl^ ^yn, 



Fig. 6. — Diagram of average haul of Plankton per month in the 

 three years, separately and combined. 



There was a decided second Diatom maximum this 



year between September 21st and the end of the month, 



very much as in '07. It gradually died away in September 



and October, and then the usual winter species of 



Biddulphia and Coscinodiscu's made their appearance in 



November. 



Plankton Outside the Bay. 



Looking at the plankton outside the bay, as shown in 



the March and April gatherings from the yacht at 



Stat. Ill, with the fine surface net, and continued by 



Mr. Dakin's hauls in much the same locality, with the 



