Summary
In a previous paper (Muntz 1973) data were presented on the visual pigments of a number of Amazonian fishes, studied by measuring the spectral absorbance of small areas of intact retinas. In some cases the corneas and lenses were found to contain yellow filtering pigments, for which spectral absorbance data were also presented. The present paper represents an extension of that work, undertaken during Phase 5 of Alpha-Helix cruise to the Amazon River system in 1977. Fishes for study were collected during January and February from nine sites near Manaus, with very different light environments, and the spectral absorbances of their retinas, lenses, and corneas measured. With the exception of one gymnotid and one tetraodontiform species, all the specimens were cichlids or carachins.