222 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



reached this lake, and here the most abundant species next to Diaptomus. With it 

 was Leptodora hyalina, also extraordinarily common (for a predaceous species) in the 

 product of every haul. The absence of Polyphemus pediculus is less remarkable, since 

 it was not common in the 'other lakes, and the fact that Holopedium gibberum should 

 be wanting here while common in Lewis Lake is without special meaning, since we 

 failed to find it in Shoshone Lake. 



A fuller discussion of this matter must be postponed until our materials illustrat- 

 ing the food of fishes taken here have been completely studied ; and I will merely add 

 at present some further details concerning the general collections. 



The beach on the west shore was gravelly, in some places with boulders of consid- 

 erable size, and occasionally with a stretch of sand. The bottom was covered with a 

 growth of weeds (Potamogeton, algae, etc.) and was greatly cumbered with driftwood. 

 Our deepest dredging was made oft' this shore, beginning at a depth of 120 feet, with 

 a temperature of 40 F., and ending at 46 feet, with a temperature of 53. This haul, 

 made from a raft and boat together, was about 100 yards in length, over soft mud 

 containing some very tine sand, but consisting largely of organic debris, both vegetable 

 and animal. The latter, minutely examined, was seen to be made up of the valves of 

 entomostraca, fragments of the cuticle of insect larvse, and the shells of rhizopods 

 (Difflugia and Echinopyxis), while the vegetable remains consisted of minute pieces of 

 Vaucheria and other filamentous alga), and fragments of higher plants, with a multi- 

 tude of shells of diatoms. The living animals of this haul were Chironomus Iarva3 and 

 pupae only, the former red, and many of them in their usual tubes composed of mud 

 and minute organic remains. 



The shallower hauls, made at a depth of 30 feet on a bottom of rock and gravel 

 covered largely with Cladophora, aggregated about 50 yards in length. A quantity 

 of material was brought up and all critically examined. It was composed almost 

 wholly of red Chironomus larvae and their tubes, together with a few specimens of 

 Pisidium. A single ephemerid larva ( Ccenis) was the only other animal found. On the 

 various alongshore hauls, at or near the bottom and through the weeds, the following 

 forms were obtained: Larvae of Chironomus, ephemerid larvae, caseworms (a single 

 specimen seen), small hydrachnids, Physa and Pisidium (only a few of each), Cyclops 

 gyrinus and other species, Diaptomus sicilis var., Daphnella brachyura, Daphnia 

 arcuata, Eurycercus lamellatus, Acroperus leucocephalus, Leptodora hyalina, Bosmina 

 longirostris and some undetermined cyprids, Stylaria lacmtris and other annelids, and 

 an abundance of Hydra fusca of the brick-red variety. The most abundant thing was 

 Daphnella brachyura, and the next Diaptomus. The Cyclops was common, as were like- 

 wise ephemerid larv;e and the small bivalve entomostracans Eurycercus and Acroperus. 



The towing-net collections, made in the open water some little distance from the 

 shore, contained a much smaller variety, all entomostraca and hydrachnids. The latter 

 were few in number, noticed only in a single haul. By far the most abundant species 

 were Diaptomus sicilis ( ?) and Daphnella brachyura, sometimes one predominating 

 and sometimes the other. With these were Leptodora and an occasional Daphnia. 



The abundance of fishes in the lake was shown by the fact that our trammel net, 

 simply stretched in the open water in the evening and lifted at noon the following day, 

 contained 87 fishes, 12 of them trout, the remainder suckers and chubs, the latter most 

 numerous. At another setting of this net, near the mouth of Witch Creek, in 8 to 10 

 feet of water, 10 trout, 2 chubs, and 65 suckers were taken in six hours. 



