Distribution of Cyclops. 
459 
The minimum percentage in the upper 9 m. was 67.6 per cent. 
(J. 10, 8 p. m.) and the maximum 99.33 per cent. (A. 2, 3 a. m.). 
The catch from the lowest 1 ex el, that from 15 m. to 18 m., 
contained on an average two specimens of Cyclops , with a 
maximum of 10, and a minimum of 0, which last result was 
found in about a quarter of the observations. The next level, 
12-15 m., contained on the average 28 Cyclops , with a maxi¬ 
mum of 79, and a minimum of 1. Diaptomus had in this level 
a maximum of 13. The average percentage of this level was 
about 1.4 per cent, of the entire number of Cyclops . The 
9-12 m. level contained on an average 176 specimens, with a 
maximum of 723 and a minimum of 1. The average percentage 
in this level was 8.77 per cent. For the entire month, there¬ 
fore, just about 90 per cent, of the Cyclops were found in the 
upper 9 meters. This distribution of Cyclops was true for the 
deeper parts of the lake, as was also found in the case of Diap¬ 
tomus. In observations made on the 21st of July, the number 
of Cyclops found between the depths of 15 and 22 m. ranged 
from 0 to 9, with an average of about 2. 
In the upper 9 meters of the lake the distribution was 
much as for Diaptomus. In the 0-3 m. level the average number 
was 683, with a maximum of 2340 (A. 4, 6 a. m.) and a minimum 
of 30 (J. 10, 8 p. m.). The average percentage of the total 
catch found in the upper level was 43, with a maximum of 66 
per cent. (J. 18, 6 p. m.) and a minimum of 17 per cent. (J. 
10, 8 p. m.). In the 3-6 m. level the average number was 612, 
with a maximum of 1944 (J. 28, 3 a. m.) and a minimum of 60 
(J. 10, 8 p. m.). The average percentage was 30.44, with a 
maximum of 59 per cent. (J. 28, 12 p. m.) and a minimum of 
16 per cent. (J. 14, 8 p. m., 18, 6 p. m.). The average number 
for the 6-9 m. level was 329 with a maximum of 1146 (A. 2, 
6 a. m.) and a minimum of 29 (J. 10, 8 p. m.) The average 
per centage was 16.35, the maximum was 46 per cent. (J. 9, 7 
p. m.) and the minimum was 5 per cent. (J. 28, 12 p. m.). 
Diurnal distribution. —In general, Cyclops shows the same facts 
of distribution by day and night as does Diaptomus , but the 
differences in distribution are not quite as plainly marked as in 
that genus. If we compare the results for the entire month, we 
