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 G-reen 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 



