416 
The absence of coarse vegetation, the sheltered situation 
in ariftin a dense forest, and the shallowness of the whole 
lake during much of the summer, permit an unusual range of 
diurnal temperature-changes falling but a few degrees short of 
the diurnal range in the air. The records (Table IX.) fre- 
quently contain readings of 90° to 95° in the summer season. 
This lake swarmed with the fry of various native fishes and the * 
introduced German carp, all of which make great inroads upon 
the vernal plankton. It was also the favorite haunt of many 
fish-loving water-fowl. This abundant animal life served in 
turn to enrich the lake waters with its nitrogenous wastes, at 
once available for utilization by the phytoplankton. There are 
thus many chains of food relations in this lake, in most of 
which, if not, indeed, in all, the plankton forms many Inks. 
COLLECTIONS, 
There is a total of 67 collections from this lake ; 1 only in 
1894, 29 in 1896, 9 in 1897, 22 in 1898, and 6 in 1899. 
The single collection in 1894 was made by the oblique-haul 
method. The absence of collections in 1895 is accounted for 
by the fact that there was no water in the lake in that year. 
In 1896-1899 collections were made in various ways according 
to the conditions of access to the lake and the depth of the 
water. Owing to rafts of driftwood, access at any season 
through the slough is prevented. At high flood-levels, when 
ice did not prevent, it was possible to enter the lake by boat 
with our plankton pump and usual collecting apparatus. At 
all other seasons access by boat was impossible,*and apparatus 
had to be carried across fields and through dense under- 
brush to the lake, and collections made by wading out into the 
lake or from a staging carried out from the shore for some dis- 
tance over the water. There are accordingly but 9 pump col- 
lections. The remaining 57 were all made by dipping water 
from the surface and pouring it through the plankton net. 
Most of the collections represent, therefore, surface waters, but 
owing to the exceedingly shoal water they are, nevertheless, in 
