SEA-FISHERIES LABORATORY. 95 
AN INTENSIVE STUDY OF THE MARINE PLANKTON 
AROUND THE SOUTH END OF THE ISLE OF 
MAN.—PART XI. 
By W. A. Herpman, F.R.S., AnpRew Scott, A.L.S.,; and 
H. Mapex Lewis, B.A. 
This research is extending over a longer period than was 
at first contemplated, but new developments of the work 
have opened up and the value of cumulative evidence has 
been impressed upon us, and, moreover, the work has been 
sreatly interrupted and hampered during the last four years 
of war. Up to 1914 eight Annual Reports upon our observa- 
tions were published in full. The Reports (Nos. IX. and X.) for 
1915 and 1916 were issued in brief abstract only. In the Report 
for 1917, we had no separate article on the Plankton work, but 
gave merely a couple of paragraphs in the “ Introduction ” 
on the Sea-Fisheries investigations in general. Consequently, 
there is now a considerable accumulation of material in the 
form of statistics of hauls, notes, curves, &c.; but the time 
has not yet come for a full and final discussion of these data, 
so we propose in the present Part to deal mainly with the 
results obtained in 1918, and the research will in all probability 
be wound up in next year’s Report. 
The work during 1918 has been carried on in the same 
manner as in previous years, so as to be comparable, and 459 
samples have been collected, preserved and examined. These 
bring the total number of samples for the 12 years’ work up 
to 5,962. In most months of 1918 well over 20 samples were 
taken, and in the more critical months (March, April, May, 
July, August and September) there were many extra hauls. 
The work at sea was carried out from the 27-foot motor-boat 
“ Redwing,” fitted with a 7 horse-power Kelvin motor, which 
