THE FINE-STRUCTURE OF THE EYE OF SERRATOS AGITTA-PSEUDOSERRATODENTATA(CHAETOGNATHA)

The eye of chaetognaths is divided by the central pigment cell into 5 unequal sectors. Each sector contains about 15 photoreceptor cells. Th e receptor cell consists of nuclear part and receptor branch formed by a modified flagellum. The basal part of the receptor branch is formed by modified ER. Its function is photoconcentration. The apical part o f the branch forms microvilli and lamellae Forming the photoreceptor o rganelle proper, the nuclear part forms an axon. Thus, each Sector of the eye can be considered as a separate eye containing its own complex of photosensitive elements.