Anatomy of Pseudotritonia Thiele, 1912 and Notaeolidia Eliot, 1905 (Gastropoda: Opisthobranchia: Nudibranchia) from Signy Island, Antarctica

Several species of nudibranch molluscs are abundant amongst the rich benthic hard substratum communities found close to the British Antarctic Survey base at Signy Island, in the Atlantic sector of the Antarctic. Over the austral summer 1992/1993, two of the authors (LWB and DKAB) were able to collect some of the lesser known species of Nudibranchia at depths between 3 and 40 metres, using SCUBA. New information on morphology and anatomy of two of these species, Pseudotritonia gracilidens Odhner, 1944 (Charcotiidae, Arminoidea) and Notaeolidia gigas Eliot, 1905(Notaeolidiidae, Aeolidoidea) are presented in this paper. The validity of the species Notaeolidia gigas is strengthened