Anatomy and ultrastructural organisation of the eye of the Mediterranean slipper lobster, Scyllarides latus: Preliminary results

Gross anatomical organisation and ultrastructure of day- and nighttime light- and dark-adapted eyes of the Mediterranean slipper lobster, Scyllarides latus, revealed that the retina of this crustacean reacts to different ambient light intensities with photomechanical changes, involving principally screening and refecting pigments and that a circadian component controls full dark-adaptation. Although similarities to the earlier investigated eyes of spiny and rock lobsters exist, one significant difference concerns the spindle shape of the adult slipper lobster rhabdom and the banded structure of the latter, caused by orthogonallyaligned layers of microvilli. The rhabdom structure of adult slipper lobsters thus resembles that of larval rock lobsters and suggests sensitivity to polarised light. The extensive clear-zone between dioptric and light-perceiving elements in the eye of the slipper lobster, the relatively large number of ommatidia and facet diameters of 90 μm, moreover, suggest that the slipper lobster eye is particularly suited for vision in a dimly lit environment and operates on the principle of "refecting superposition optics". The position of the eyes on the head and the thick cornea are indicative of a need to protect the eyes against physical damage.