218 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



The small brown lagoon or pond already mentioned as occurring near the lake 

 was an example of a kind quite common along the lake borders of this region. It is 

 separated from the lake itself only by a narrow strip of beach, and is largely filled 

 with pond lilies (Nuphar], grass, algiB, and the like, which grow out of a deep, soft 

 ooze. There was little in the assemblage of animal forms of this place to suggest its 

 elevation of more than 7,000 feet, unless the scarcity of mollusks and the higher Crus- 

 tacea be so explained. A species of Physa and one of Pisidiu.m were the only mollusks 

 taken. Insects were represented chiefly by ephemerid larvae, larva; of Culex, Chirono- 

 mus, and other small Diptera, caseworms, Notonecta, Gorisa, Agrion larvae, and larvse 

 of Dytiscidw; Hydrachnidce by a single species of scarlet water-spider; AmpMpoda 

 by the lake species Gammarus robustus and Allorchestes dentata; eutoinostraca most 

 abundantly by a Daphnia of pale pink color, not seen by us before, and here described 

 as D. angulifera, by D. pulex in moderate numbers, by Polyphemus, Scapholeberis 

 mucronatm, Eurycercus lamellatus, Chydorus, Cypris, Cyclops gyrinws, G. serrwlatus, 

 etc., and by no Diaptomi, so far as observed. Leeches were present, although not 

 numerous the species already mentioned (Nephelix maculata) and one not detected in 

 the lake, Aulostoma lacustris Leidy. This pond thus differed from the lake in the 

 larger number and variety of insects, especially in the larval state, by the absence 

 of Diaptomi, and by the vast predominance of the new Daphnia. The latter had 

 evidently been very much more abundant earlier in the season, as shown by the quan- 

 tities of its summer eggs. These formed a film over many square feet of the surface 

 and had been washed ashore in quantity as a scum-like deposit along the bank. A 

 few of the females were still bearing their ephippia. 



The collections made by Prof. Linton from the lagoon at the western end of the 

 lake are similar, as far as they go, but contain no entomostraca. 



Lewis Lake. Lewis Lake is so closely associated with Shoshone that the two 

 might very well be treated by the biologist as one. The water, shores, bottom, and 

 surrounding country have substantially the same characters for both, and their free 

 connection by a river without falls and only some 3 miles in length tends to oblit- 

 erate any small local differences. The fact that fishes are excluded from both lakes 

 by falls in their common outlet still further assimilates them in biological condition, 

 the only noticeable differences remaining being those of size and depth. 



Lewis Lake is but 3 miles long by 2J in breadth, with a greatest depth, in our 

 soundings, of 80 feet. It is rudely triangular in form more distinctly heart-shaped, 

 in fact, than Heart Lake itself. Its level, 7,720 feet, is but 20 feet below that of 

 Shoshone Lake. Its western banks are highest and boldest, the 8,000-foot contour 

 running usually from a quarter to half a mile from the shore. On the north and 

 northeast the country is relatively low toward Shoshone and Yellowstone lakes, but 

 the immediate banks are occasionally bluffy and the shores are everywhere wooded. 

 The Bed Mountains are close at hand, a range of ten peaks to the southeast; and to 

 the south looms the great Teton group, the noblest mountain view to be had from 

 any part of the Park. 



There is a small hot-spring basin at the northwest angle of Lewis Lake, and a 

 swampy tract about half a mile square lies beside it to the northwest, connected with 

 it for a fortnight or so during high water. At other times communication is prevented 

 by a narrow strip of beach, sand and gravel, a few feet across. At a little trouble 

 and expense a permanent passage-way for fishes might be made and maintained, giving 

 free access to considerable breeding-grounds and stores of food. 



