THE SAND ROLLERS 



Family XXIV. PercopsidcB 



This small family is of special interest because it combines 

 with ordinary Salmonoid characters the structure of the head and 

 mouth of the Percoids, as may be seen by the accompanying 

 illustration. Only 2 genera known, each with a single species. 

 Percopsis guttatus, the common sand roller or trout perch, is found 



in lakes and suitable streams from Lake Champlain and the Del- 

 aware River, west to Kansas and Assiniboia. It prefers cold, 

 clear waters, and is most abundant in the Great Lakes, particu- 

 larly in Lakes Michigan and Superior. It spawns in the spring, 

 at which time it runs into tributary streams in great numbers. 

 Mr. Andrew Halkett, Naturalist of the Department of Marine and 

 Fisheries, Ottawa, informs us that immense numbers are seen in 

 the Moira River every spring. 



Though reaching a length of only 6 or 8 inches, the sand 

 roller takes the hook readily, and is used as a pan-fish. We 

 have seen boys on the Chicago piers catching them in great 

 numbers. Colnmbia transmontana is known only from the 

 Umatilla River at Umatilla, Oregon, and the Walla Walla River at 

 Wallula, Washington, both places in the Columbia River Basin- 



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