397 
4-fold that in the river (.74 and 2.39),so that the run-off at this 
season enriches channel plankton. With the exception of the 
August collection the plankton content in the other three col- 
lections in the lake exceeds that in the stream. The low con- 
tent in August (1.08) occurs at atime of lowest water, when 
vegetation by reason both of river stage and the season is at its 
maximum occupancy of the lake. At other times the effect of 
the reservoir function of the lake is seen in the relatively great- 
er production in its waters. 
The scattered data of this year are insufficient as a basis 
for any conclusions as to the correspondence in the movement 
of production in this and other waters. 
1895. 
(Table VIII, Pl. XXXVI.) 
There are 14 collections in this year, between April 10 and 
the end of the year, averaging 9.67 cm.’ per m.*, and with a 
maximum of 61.44 on May 1—an amplitude nearly 11-fold that 
of this pulse in the channel. 
The average production (9.67) is 3-fold greater than that 
of the river in this year (3.22), and the monthly averages (see 
table between pp. 342 and 343) are in 5 of the 9 months from 1.6- 
to 12-fold greater in the lake than in the river. In the remain- 
ing four months, June, July, August, and December, the ratios 
are respectively 30.42, 9.33, 4.03, and 1.14 (river), to 9.42, 4.85, 
3.09, and 1.00. The lower production in June-August occurs at 
atime when, with the exception of three weeks, levels were low 
and vegetation at its maximum occupancy of the lake, and when, 
moreover, the current was greatly slackened in the river, and 
channel plankton in the richly fertilized waters had more than 
the usual time to breed, while the less production in the lake 
in December is, owing to the distribution of collections, more 
apparent than real. 
In the matter of individual collections on coincident or 
approximate dates the lake shows a greater plankton content 
in 9 out of the 14 instances, and of the 9 there are 5 in which 
