A DESCRIPTIVE STUDY OF SOME ANTARCTIC NOTASPIDEAN OPISTHOBRANCHS (GASTROPODA), WITH DESCRIPTION OF A NEW GENUS AND SPECIES

During the expedition ''ANTARTIDA 9101'', organized by the Spanish Oce anographic Institute to the South Orkney Islands, four specimens of no taspidean gastropods were collected. Three of them have been identifie d as Bathyberthella antarctica Willan and Bertsch, 1987. However, one specimen, although externally similar to B. antarctica, had an interna l anatomy exhibiting features that have enabled us to consider it to b e a new genus and species. This new taxon is characterized by the pres ence of jaws without mandibular elements, and a vaginal gland that par tially surrounds the distal region of the vaginal duct. In this paper the new genus and species is described. Additional anatomical data of the specimens of B. antarctica collected during the expedition are als o included.