395 
ize environmental fluctuations and to obviate their catastrophic 
results, which may be seen in their maximum violence in 
channel waters, and in a lesser degree in the lakes thus far ex- 
amined, 
COLLECTIONS, 
This station was opened June 7, 1894, and collections were 
continued until the close of operations on March 28, 1599. In 
all, 99 collections were taken, distributed in the several years 
as follows: 5, 14, 27, 18, 25, and 7, with but few exceptions at 
approximately a monthly or fortnightly interval. It was only 
in the spring and summer of 1896, when an interval of 7-10 
days was adopted, that the interval is brief enough to enable 
us to trace the movement in production with any degree of 
fullness. At other seasons the data are suggestive, but not 
conclusive, of its course. The relatively smaller number of 
collections made at this important station is due to its distance 
from our center of operations, the round trip from Havana to 
the lower station in low-water conditions exceeding 25 miles. 
The difficulties of access were greatly increased when at low 
water it was necessary to make the trip from the outlet of the 
slough by rowboat, and to drag or push this over the soft mud 
and through the dense vegetation at the upper end of the lake, 
and when, in winter, at low water, the boat and outfit had to 
be dragged across the frozen bottom-lands. 
The locations at which collections have been made are 
principally the two marked on the map (PI. II). The lower 
one was used exclusively in 1894 and 1895, and thereafter 
when access to the lake was had through the cut road. The 
location off Sand Point, at the upper end, was used when the 
lake was entered by way of the slough. Both were in the open 
central region, well out in the vegetation-free area, though in 
1895 and 1896 the lower station was encroached upon some- 
what by shifting masses of Ceratophyllum. In a few instances, 
owing to high southwest winds and the dragging of the waves 
in the shallow lake, it was not possible to maintain an anchor- 
