196 
Marsh—Limnetic Crustacea of Green Lake. 
epischura lacustris— continued. 
Per cent. 
No. Total, 
of Coll. No. 
0-5 
5-10 
10.96.. 
11.96.. 
12.96.. 
13.96.. 
14.96.. 
15.96.. 
16.96.. 
17.96.. 
18.96.. 
19.26.. 
20.96.. 
21.96.. 
22.96.. 
23.96.. 
24.96.. 
25.96.. 
26.96.. 
27.96.. 
140 
131 
54 
30 
29 
203 
397 
333 
270 
107 
100 
120 
46 
150 
46 
98 
9 
4 
61.43 
61.07 
44.44 
53.33 
27.59 
99.01 
84.63 
76.58 
91.48 
61.68 
28. 
46.66 
34.79 
69.33 
69.56 
93.88 
in0.20 
100 . 
34.29 
7.63 
44.45 
13.33 
48.28 
.99 
11.34 
21.32 
37.38 
72. 
40. 
34.78 
21.34 
15.22 
met’rs 
10-15 
15-20 
20-25 
25-30 
30-35 
35-40 
40- 
1.43 
30.54 
11.11 
33.34 
20.68 
.71 
.76 
.71 
1.43 
3.45 
4.03 
1.80 
.30 
5.93 
2.22 
.94 
.37 
i3.34 
26.09 
5.34 
15.22 
2.17 
2.67 
2.17 
.66 
.66 
3.06 
1.02 
2.04 
From the table it appears that Epischura occurs in the sum¬ 
mer and fall months, with no very well defined time of maxi¬ 
mum numbers. (See PI. VIII.) The largest numbers obtained 
at single hauls were 390 in the evening of October 9, 1894, 
395 from a haul made through the ice on March 9, 1895, and 
397 on August 24, 1896. In the March haul a large proportion 
were larval forms. Epischura disappears entirely in the latter 
part of March and does not appear again until June. 
The number of my winter collections was, unfortunately, very 
small, so that one must be very careful about drawing infer¬ 
ences from them. But I think we may consider it fairly cer¬ 
tain that Epischura is hatched from the egg in the winter,— 
probably in February or the early part of March. This in itself 
is a matter of some interest, as, so far as I know, there is no 
previous record of the occurrence of any considerable number 
of larval forms of Epischura. 
It is a curious fact that so soon after the appearance of the 
larval forms, Epischura entirely disappears for several months. 
I will not in this paper hazard a conjecture as to the explana- 
