THE NATURE OF THE GECKO VISUAL PIGMENT

Abstract

Retinal extracts of the Australian gecko, Phyllurus milii (White), have revealed the presence of a photosensitive pigment, unusual for terrestrial animals, because of its absorption maximum at 524 mµ. This pigment has an absorption spectrum which is identical in form with that of other visual chromoproteins. It is not a porphyropsin, for bleaching revealed the presence, not of retinene₂, but of retinene₁ as a chromophore. Photolabile pigments with characteristics similar to those of the Phyllurus visual pigment were also detected in retinal extracts of six other species of nocturnal geckos.