180 Marsh—Limnetic Crustacea of Green Lake. 
The work was commenced in the latter part of September, 
1894, During the fall the lake was visited twice each week, 
and at each visit from one to four series of collections were 
made. In the winter, while the lake was closed by ice, only 
three collections were made. From the latter part of April, 
1895, until July, collections were made at intervals of about 
one week. In July and August no collections were made, but 
in September the work was resumed, and collections were made 
at intervals of about one month until July, 1896. From July, 
1896, to December, weekly collections were made. Thus I had 
a series of collections running through a little over two years, 
with the exception that for the months of July and August, I 
had only the collections of 1896. 
During the time in which this work has been going on, con 
siderable has been published on the periodicity and distribution 
of the limnetic Crustacea, so that some of my results are simply 
corroborative of the work of others, especially in regard to the 
seasonal distribution of the Crustacea. The peculiar character 
of Green Lake and its fauna and flora, however, makes simply 
corroborative work important, and some of the results, I think, 
are entirely new. 
I wish to acknowledge the very efficient assistance of Mr. 
P. S. Collins, of Ripon, in the work of making the collections 
and observations. Sherwood Forest Hotel was the headquarters 
of the station work, and I am greatly indebted to the proprie¬ 
tor, Mr. Beckwith, and Mrs. Beckwith, for innumerable courte¬ 
sies. 
GREEN LAKE. 
The general character of Green Lake has been indicated in my 
former paper. (Marsh, ’91, b.) It is a long, narrow body of 
water, something over seven miles in length, and with a maximum 
width of less than two miles. At the eastern end where it is 
fed by a small stream, Silver Creek, the shore is low and swampy. 
At the western end another small stream enters, and here also 
the shore is low, but most of the shore line is made of bluffs of 
greater or less elevation. At Lucas’s Point and Sugar Loaf are 
abrupt cliffs of Potsdam sandstone. There are a large number of 
