AQUATIC INVERTEBRATE FAUNA OF WYOMING AND MONTANA. 
235 
Our collections were made with a surface net in deep and shallow water, with a 
dredge at a depth of 30 feet (the greatest found), and with the hand net from grass 
and lily pads near the margin, from the gravelly bottom in shallow water, and from 
weedy mud — this list exhausting, in fact, all the varieties of situation offered. 
The lake lies north and south in greatest length, the outlet leaving the south end 
and flowing to the south at first. It is in some respects a duplicate of Mary Lake, 
but is somewhat larger, being half to three-quarters of a mile long and about two- 
thirds as wide. It is of oval form, with grassy margins, commonly sod to the water’s 
edge, rimmed round with lily pads and other water weeds, and witli a bottom of soft, 
black mud. The banks were somewhat swampy, but the ground was higher to the 
north and west. Three small streams flow into the lake, one from the northeast and 
t wo from the west. 
Although so unlike Shoshone Lake, its assemblage of animal forms bore a striking 
resemblance to that of the larger, clearer lake. The absence of fish, the abundance 
of Gammarus and Diaptomi , and the scarcity of Daphniidce are examples. On the 
other hand, the grassy borders and weedy shallows entertained a much greater abun- 
dance and variety of insect forms than the hard and bare margins of either Shoshone 
or Mary Lake. 
In the mud of the bottom were many large red Ghironomus larvse, a few speci- 
mens of Gammarus , and the usual Pisidium. The entomostraca were mostly JDiapto- 
muslintoni , which replaced in this small lakelet the J). shoshone of the other lake; here 
also we found Daphnia clathrata , n. s., the only locality thus far discovered for it. It 
was not abundant in Grebe Lake, and may have bred primarily in the swamps adjoin- 
ing. A species of Cyclops also occurred here in small numbers, which is described on 
page 24S as G. capilliferus. 
Inshore collections were unusually fruitful. Gammarus and Allorchestes were very 
abundant along the margin in the weeds and grass, and Pisidium especially was 
extraordinarily common. Here also were agrionine and ephemerid larvae, caseworms 
with cases of fine sand, Gorisa , Pisidium , Physa , Ghironomus , and Spongilla , and on 
the mud among grass and algae were dytiscid and small sialid larvae, Pliysa and Pisid- 
ium ., Nephelis and Clepsine , Allorchestes and Gammarus , Ghironomus and ephemerid 
larvae, larvae of dragon-flies, and specimens of Haliplus. 
This lake was an additional illustration of the fact that, in this high mountain 
region, where aquatic life seems oppressed with unusual difficulties, change in cir- 
cumstance takes extraordinary effect, so that each lake has its distinct and special 
zoological character. 
