Description:
<jats:title>ABSTRACT</jats:title><jats:p>The circadian oscillation of sensitivity of the anterior median eye of a nocturnal spider Araneus ventricosus and that of a diurnal spider Menemerus confusus were examined by recording electroretinograms. The anterior median eye of Araneus ventricosus showed a marked circadian oscillation of sensitivity, but that of Menemerus confusus showed no circadian oscillation.</jats:p>