A survey of the literature reveals no works concerned with the visual cells of the silverjaw minnow (Ericymba buccata), although Brown ( '36) has shown that this species, like many others, undergoes color changes in accordance with the ratio of incident and reflected light striking the eye of the animal.This study was undertaken upon the suggestion of Mr.Milton B. Trautman who is engaged in ichthyological studies of Ohio fishes. Mr. Trautman became interested in the eyes of Ericgmba, since his field observations indicated that this form is quite capable of withstanding considerable differences in silt content of the waters in which it lives. The following statement is abstracted from his letter of January 5, 1949: "The species is well distributed over Ohio and, therefore, somewhat tolerant of turbid water. However, it is abundant only in the clearest of the smaller streams which have plenty of sand and a moderate gradient. Ericymba seems to prefer to lie over clean sand and seemingly is quite phototropic. In a brilliant noonday sun when other species had retired to the shade, I have seen large numbers over bright white sand in clear water. Ericymba hides under 1Contribution from the Department of Zoology (no.