214 BULLETIN OF THE UNITED STATES FISH COMMISSION. 







The systems to which the various waters examined belong are those of Snake 

 River and the Columbia on the Pacific slope, and of the Yellowstone and the upper 

 Missouri on the Atlantic slope. The first is represented by collections made in the 

 southwest part of Yellowstone Park, the second by those from the Flathead region, the 

 third from the north and eastern parts of the Park and from the vicinity of Boteler's 

 Ranch, and the fourth by those from the branches of the Madison in the central- 

 western part, and from Bridger Creek near Bozeman. 



The collections now reported were made from the waters named in the following 

 list : A mountain pond near Norris Pass, Shoshone Lake, Lewis Lake, Heart Lake, 

 Yellowstone Lake and certain of its tributary waters, Duck Lake (near the Yellow- 

 stone), Mary Lake, Goose Lake, Twin Lakes, Lake of the Woods, Grebe Lake (at 

 the head of Gibbon River), Swan Lake (Yellowstone Park), a lakelet near Mammoth 

 Hot Springs, Trout Lake (near Soda Butte), small ponds in the Soda Butte bottoms, 

 alkaline ponds near Baronette's bridge and several other scattered ponds, Flathead 

 Lake, and Swan Lake (Montana). 



THE SNAKE RIVER SYSTEM. 



This system was reached only in its head waters, all a few miles from the low "con- 

 tinental divide," which sometimes separates only imperfectly the waters of the Pacific 

 side of the continent from those of the Atlantic slope. Shoshone and Lewis lakes of 

 this system are, respectively, about 1 j and 2 miles in a direct line beyond the crest of 

 the divide, and Heart Lake is less than 4. From these lakes and from their tribu- 

 taries all the collections made in this district were obtained, with the exception of a 

 little group snatched with the hand net, while the pack train was passing, from a 

 mountain pond near Norris Pass, on the Shoshoue trail. 



This pond was completely stagnant and filled with growing vegetation (including 

 filamentous and gelatinous algae) and fallen timber. The collection contains little to 

 indicate the elevation from which it came, but is of interest in comparison with the 

 contents of the very different waters of Shoshone Lake a few miles away and 400 

 feet below. In this pond I found a small spotted larval salamander, with both fore 

 and hind legs already budded out, a considerable number of young insects (Corisa, 

 Chironomus, and Gorethra larva and pupa), an amphipod crustacean (Allorchestes 

 dentata), and a great number of entomostraca. Among the latter were Diaptomus 

 shoshone,* two species of Cyclops, Daphnia pulex, an undetermined species of Daphnia, 

 and a Geriodaphnia. A black springtail (Poduridce) and a wheel animalcule (Lacinu- 

 laria socialis), occurring abundantly in globular colonies, were the only other animals 

 recognized in this preliminary examination. 



Shoshone Lake. Shoshone Lake is a lovely little body of clear blue water lying at 

 the level of 7,740 feet almost exactly that of Yellowstone Lake. It is shaped like a 

 blotted T, with the stem, 7 miles long, extending north of east from the Geyser Basin, 

 at the head of the lake, and the crosspiece, at the eastern end, about 4 miles in length. 

 The stem reaches a width of 1 J nules, but narrows near the middle of the length of the 

 lake to less than half a mile. This lake lies charmingly secluded in a hollow of the 

 densely wooded mountains which surround it everywhere except to the southeast. It 

 is at present accessible only by mountain trail from the Upper Geyser Basin, and has 

 fortunately been omitted from the system of improved roads now being made for wagon 



* Described on pagu 251. 



