Abstract
Photoreceptor cell outer segments of five different morphologies from frog and tadpole retinas have been examined by microspectrophotometry. Photosensitive pigments were found with the following λ max : Frog: red rod 502, green rod 432, principal cone 575, accessory cone 502, single cone 575; Tadpole: red rod 527, green rod 438, principal cone 620, accessory cone 527, and single cone 620. Axial densities of pigments are computed from their measured transverse densities. A 2 derived pigments have wider bandwidths on a wavenumber plot than A 1 based pigments. Red rod wavenumber plots match published nomograms but other pigments do not. All pigments are dichroic and have comparable photosensitivities. Molar concentration of visual pigments is nearly the same in all cells. However, the small size and number of cones in frog retinas probably makes the total relative contribution of cone pigment molecules too small for successful spectroscopic studies in extracts. Animals in the visual pigment phase of metamorphosis have identical pigment mixtures in all red rods.
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