Identification of Bifurcate Paraocular Process and Postocular Filamentary Tuft of Facetotectan Cyprids (Crustacea : Maxillopoda)

Abstract

The ultrastructure of the bifurcate paraocular process and postocular filamentary tuft in an undescribed form of facetotectan cyprid from the North Pacific was examined using TEM. The bifurcate paraocular process is proximally accompanied by cilia that give rise to complex, lamellar structures, and appears to be an external portion of the organ of Bellonci, which is well known in cirripedes and some other crustaceans. The postocular filamentary tuft is an aggregation of filamentary extentions arising from cells that are part of a prominent organ located posterior to each compound eye. This organ is probably a gland, similar in position and cell composition to the cement gland known in cirripede cyprids, though its actual function is still unclear.