412 
Birge—The Crustacea of the Plankton. 
Table XXXVII.—Continued. 
The preceding tables show the results of some of the more 
important observations of this kind made in 1897. The fig¬ 
ures of these tables express the rate per cubic meter found at 
the given depths, not the actual population between certain 
depths as is done in the tables based on the vertical net. 
In most of these lists, the preponderance of Cyclops in the 
upper stratum is striking. In A, all of the Diaptomi at 0.5 and 
1 m. were young. The same was true of D. hyalina at 0.5 m., 
and above. In all catches 85-95 per cent, were young at 1 m. on 
sunny days. The effect of cloud is plainly visible in B, C, and 
F, and of wind in E and G-. The tendency of Gloiotrichia to 
aggregate at the surface is well seen in D. 
In the following tables the record for two more complete ob¬ 
servations is given, together with one illustration of a night 
distribution. In the latter there were almost no nauplii, an 
exception to what has usually been found at night. The popu¬ 
lation for the given depths in the catch of September 8th has 
been platted in Fig. 33, and Fig. 32 shows the upper three 
meters of the two sets of observations on September 13. 
