Etude cytologique des organes photorécepteurs de la Planaire australienne Cura pinguis

Abstract

The photoreceptors of the australian planarian Cura pinguis were studied by light and electron microscopy. They consist of two different cell types (=primitive type), a cup of pigment cells, and 25 to 30 bipolar visual cells. Cytoplasmic extensions of the pigment cells close the eye opening but leave the dendritic stalk free. This study shows that the morphological characteristics suggest a metabolic cellular activity with the presence of components implied in the visual processes. In animals kept in the dark, the microvilli have a less regular appearance and some material accumulates in the spaces between the visual and pigment cells. The efferent innervation displays a narrow connection with the brain.