- EXPLANATION OF PLATES. 

PrArE Ie 
Seasonal distribution of synthetic groups of planktonts, Chlorophycee, 
Bacillariacee, and Mastigophora, from July 1, 1895, to October 1, 1896. Note 
changes of scale indicated at bottom of diagram. Numbers in column at left apply 
only to 1895. In this plate and in II. and IV., apices exceeding the limit of the 
diagram are dropped down between dotted lines to show location. Circles at 
bottom indicate location of day of full moon. 
Prare le 
The same as above, from July 1, 1897, to April 1, 1899. Note change in 
scale from previous plate. 
Piranesi: 
Seasonal distribution of total Rotifera and Crustacea from July 1, 1895, to 
October 1, 1896. The Crustacea included, belong almost exclusively to the Ento- 
mostraca. Apices exceeding the limits of the diagram are dropped down between 
dotted lines to show location. Totals include both adult and immature stages of 
the Entomostraca when detached from parent, and both free and attached eggs of 
__ the Rotijfera. 
PuaTte IV. 
The same as above, from July 1, 1897, to April 1, 1899. 
PiatTeE V. 
Seasonal distribution of Polyarthra platyptera. Total number of individuals, 
not including eggs, represented by ordinants, parts of which exceeding 200,000 
are represented by diagonal lines instead of solid vertical lines. Thus parts of a 
seasonal plot which overlap those above it on the plate are represented by the 
diagonally-lined ordinants. 
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