THE ULTRASTRUCTURE OF THE SENSORY DORSAL ORGAN OF CRUSTACEA1)

摘要: The present study compares the ultrastructure of "dorsal organs" on anterior, dorsal carapace syncarid Anaspides tasmaniae and crangonid shrimp Crangon crangon. Although species are not closely related phylogenetically, elements their organs arranged differently, they remarkably similar ultrastructurally. common include an island thinner epicuticle lying across aperture a hole through surrounding cuticle, squarish in case Anaspides, lozenge shaped Crangon. This whole area appears to be flexible. At centre thin region is tabular invagination cuticle ending blindly with pore at bottom tube surrounded by single large cell extensive internal membranes basal vacuoles or vesicles. part organ innervated. Four small papillae disposed about this central region, quincunx formation pair each side row thins further over underside associated four sensory dendrites so that innervated total sixteen neurons. beneath papilla have bodies cilliary microtubules typical mechanosensors. close tips non-cellular material separated from other series sheath cells. On basis similarity, because relationship between these elements, as evidenced studies external structure wide range taxa, strongly conserved, we propose described here belong particular class which call (of Laverack). ultrastructure, conservation proximity