106 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
UNITED STATES. 
The region about Umatilla is a rolling prairie. The banks of the Columbia River 
are sandy and gravelly. The Umatilla River is small and empties into the Columbia. 
About its mouth is an estuary with a soft mud bottom and with from 2 to 3 feet depth 
of water. The mud and some waterweeds usually filled the net so that it was difficult 
to pick out the fish, especially as it was necessary to collect after dark. The most 
important discovery of the season was made at this point. Golmibia transmontana 
shows in a striking way the modification of the fins of the Pacific slope fishes. In 
this case it has found expression in the strong spines at the origin of the anal and the 
dorsal fins. 
The Grand Ronde River is a tributary of the Snake. At La Grande it is a small 
stream with a few deep holes. It is dammed near the town for milling purposes, is 
full of angular pieces of lava, and seining is almost impossible. Below the dam large 
numbers of Animocoetes were found dead. 
About Caldwell the country is a level plateau, treeless except along the river banks. 
The Boise River, which is a swift stream about 100 feet or less in width, is dammed at 
various places to divert the water into irrigating ditches. There are level stretches 
in the river, alternating with swift riffles. 
At Idaho Palls the Snake River has woi ii a narrow gorge through the lava, and is 
a fierce torrent in which seining was out of the question. Fortunately a small stream 
has been diverted for a mill, and in this 1 obtained ])r()bably a complete series of the 
fishes of this region. The country is still a level valley with mountain ranges at a 
distance on either side. 
Soon after leaving Idaho Falls the continental divide is crossed. The first station 
at which I made collections was Craig, Mont., on the Missouri. This river is here 
about 150 feet wide, a clear, cold, rapid stream with gravel bottom and full of Core- 
gonus Williamson, i nad Platygohio gracilis. Fishing was confined chietlj^ to the slough 
formed at the mouth of a small creek entering: from the eastern side. 
At Poplar the Missouri is a swift, muddy stream, probably 200 jmrds or more wide. 
Poplar River is also muddy and partakes of the nature of the prairie streams near 
Winnipeg: that is, its banks are composed of soft mud. It seemed nowhere over 5 
feet deep, and in many places it was only a foot deep. 
