Ainerican Fisheries /'Society. 319 



tlie higher regions are melting, is considerable, but is said to 

 dwindle markedly later in the summer. In the course of this 

 brook and its branches are located the half dozen smaller lakes 

 which were the particular objects of this study. They are known 

 locally as Grass Lake, Lily Lake, Suzy Lake, Heather Lake, 

 Half Moon Lake, Gilmore Lake, and their similarity is rather 

 striking. In size, from a quarter to a half mile in length, they 

 are for the most ])art deep pockets with little or no shore area 

 and vegetation, and with the major portion of the margin and 

 bottom of rock formation. In altitude they vary from (5, 300 feet 

 to about 8,000 feet. At the time of the \isit the lower lakes were 

 entirely free from ice and snow, and the water had risen at the 

 most favorable points to a temperature of sixty to seventy d(>- 

 grees. althougli this ol)tained only over limited areas of surface 

 water. At the same time the upper lakes Avere still ice-bound ir 

 part and fed exclusively by mountain snow banks, so that the 

 temperature of the water was everyhere low. 



I made a series of collections, both from the shore and deep 

 water in these lakes, and the result of the same is shown in the 

 table at the close of the ])aper. It was indeed remarkable that 

 the lakes contained so little in the form of microscopic life. 

 Xeither plant nor animal forms seemed to be present in consid- 

 erable numters or in any variety. A few of a single species of 

 entomostracan was all that any lake contributed from tliis groiiji, 

 "wdiile in some not a single member of it was captured. A]i])ar- 

 ently, then, at this season the microscopic Crustacea (an atVoi'd lii- 

 tle or nothing in the way of food supply for the lakes. In shal- 

 lower pools adjacent and sometimes connected witli the birger 

 lakes I found numbers of these forms; t)ut still more mnnei-ous 

 and striking was the development of insect larva(\ These col- 

 lections are also noted in the table. The trout which were caught 

 in the different lakes varied greatly in robustness. From cer- 

 tain lakes they came plump and well fed: from others, however, 

 the fishermen reported that they were '-all head," having had a 

 hard time during the winter, and being thin and poorly nour- 

 ished at present, a fact which stands in interesting connection 

 with the absence of the plankton organisms from these lakes. 



One other interesting fact deserves mention in this connec- 

 tion. I was i)rivileii(Ml to t'xamine tlie stouiacli contents of a 



