238 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
tenths of the product of every deep-water haul with the surface net. Diaptomus , the 
text lommonest form in Yellowstone Lake, was not certainly seen at all in Flathead, 
but was replaced by a new variety of Epischura (E. nevadensis , var. Columbia;), which 
held practically the same relation to Daphnia tliorata which />. sicilis held to D. pulex 
in the other lake. Besides these most abundant pelagic forms we found only occasional 
examples of Leptodora , Cyclops ,* Bosmina , Scaplioleberis , and S ida crystallina, the 
last two shore forms which probably would not have been taken very far out. Be- 
tween the deeper waters and the weedy northern margin of the northeast bay is an 
extensive Hat of sand, under from 5 to 15 feet of water, and here our tow-net hauls 
were always remarkably unproductive. Partly, perhaps, because of the barrier offered 
by this barren belt of shallow water, the pelagic Crustacea did not appear at all in 
our alongshore collections as they did in Yellowstone Lake. The assemblage of forms 
brought out by the small amount of work inshore which we had time to do, was in 
no way remarkable, unless for its deficiencies. Gammarus and Allorchestes dentata 
among the amphipod crustaceans, Sida, Eurycercus, and Cyclops gyrinus among the 
entomostraca, species of Pliysa, Limnasa , and Planorbis among mollusks, and the usual 
miscellany of hydrachnids, epheinerid and Chironomus larvae, larvae and adults of 
Dytiscida ; and Hydrophilidce , Corisa , plauarians, leeches, and annelids — among the 
latter, Pristina lacustris — were the commoner kinds. 
Our first dredging in Flathead Lake was made about 200 yards from land, olf the 
mouth of a small cove with bluffy shores — the first below the Helena Club House — 
in water ranging from 76 to 125 feet. The dredge came up, after a haul of about a 
quarter of a mile, well filled with soft mud, mostly of slaty color, but somewhat 
streaked with reddish brown and mixed with a considerable debris of particles of 
dead wood, fragments of dead leaves, cast skins of insect larvrn, and the like. 
The greater part of the zoological product of this haul was a mass of the coene- 
cium of a species of polyzoan ( Plumatella , near arethusa .), and with these came Chi- 
ronomus larva;, red and pale, a dozen specimens of Pisidium , a few cyprids, and a 
number of undetermined, slender, pale-red, annelid worms, 2 to 3 inches long and a 
millimeter in diameter. 
The second dredging was made in the same vicinity, but a little below the pre- 
ceding and farther out. Beginning about half a mile out from the head of the same 
cove, at a depth of 125 feet, we hauled nearly a mile to south and west, taking up the 
dredge at a depth of 153 feet, when about three- fourths of a mile from the point form- 
ing the southern limit of the cove. This haul yielded precisely the same product as 
the other — an abundance of the same species in approximately the same ratios. 
Neither in variety nor quantity was the animal life of the deeper waters of this 
lake, as shown by our work with the dredge and towing net, at all in advance of Yel 
lowstone Lake, with the single exception of the polyzoan of our dredgings, and this 
was possibly only a local accident. , 
The bottom and margins of the southern end of the lake seemed comparatively 
barren, the weeds washed ashore containing, in fact, scarcely anything but Allor- 
cliestes dentata , dytiscid and ephemerid larvae, and Corisa. From the stony fiat at 
the outlet a considerable supply of caseworms of several species was obtained, Corisa, 
* Mostly a species undescribed, allied to thomasi of the Great Lakes, but differing in its more 
slender, more loosely articulated form and in the armature of some of its legs. 
