Myer-Rochow, V.B. ; Reid, Walton A
Author Affiliation, Ana.
Electron Microscopy Unit
Cephalic structures in the memertine parborlasia corrugatus -Are they really eyes?
Tissue and Cell
Date of Publication
The opinion as to whether tiny, approximately 0.1 mm large spots around the innermost margin of the cephalic slits in the Antarctic nemertine worm Parborlasia corrugatus represent photoreceptors or not has fluctuated over the years. This first electron microscope study of the enigmatic spots fails to detect any screening pigment granules, rhabdomeres, or lamellae, but reveals that the structure in question is principally made up of two types of cell, characterized by vesiculat and veacuolar material of approximately 80 nm and 0.3 Ám in diameter, respectively. Filamentous connective tissue strands with gaps for axons surrounds the 'eye-spot' and it is suggested that either exposure to the bright Antartic summer light has led to a total disintegration of all visual membranes or these structures do not represent eyes at all.....