Photoreceptor fine structure in the vervet monkey (Cercopithecus aethiops).

The structure of the photoreceptors of the vervet monkey (Cercopithecus aethiops) has been investigated by light and electron microscopy. In this species the photoreceptors can be readily differentiated and adequately described by the classical terminology of rods and cones, with rods being the more numerous. Rods are long, slender cells while cones are shorter and stouter. Both rods and cones are highly differentiated cells and consist of an outer segment, a connecting cilium, and inner segment, a nuclear region and a synaptic process leading to a synaptic ending. Morphological differences are noted between rods and cones for the various regions of these cells.