A quantitative study of the optic system of butterflyfishes (family chaetodontidae).

The following measurements were taken on the visual system in 13 species of butterflyfishes (family Chaetodontidae): volume and cell density of the nucleus geniculatus lateralis, nucleus corticalis, and nucleus pretectalis; and width of the stratum opticum-stratum fibrosum et griseum superficiale. Tests for correlations between these components showed that the volumes of the nucleus pretectalis and nucleus corticalis are positively correlated. No significant differences were found when the volumes and cell densities of these parts were compared in two groups of butterflyfishes whose feeding behaviors are different: plankton feeders and coral feeders. A possible spurious positive correlation between the sizes of the nucleus pretectalis, nucleus corticalis, stratum opticum-stratum fibrosum et griseum superficiale and total body length was also demonstrated.