J. Moll. Stud. (2001), 67, 243–246 © The Malacological Society of London 2001 Gastropods belonging to several families are known to be specialist feeders upon cnidarians. 1 Coralliophila meyendorffii (Calcara, 1845) is a muricid neogastropod (Coralliophilinae) commonly occurring in the northeastern Atlantic (including the Mediterranean sea). Contrary to the usual habit of most coralliophiline species, C. meyendorffii feeds upon a wide range of cnidarian prey. Two main morphological forms are encountered (Figs 1–4), 2 which show discrete differences in size, ecology (cnidarian prey) and reproductive biology (shell length at sex change). A large sized form (adult females 8–40 mm length) is found associated with sea anemones, feeding by boring into the stalk wall. Females with egg capsules in the mantle cavity are encountered above a size of approximately 8–10 mm, at which sex change is assumed to occur. A small form (adult females 4–9 mm length) is found on sclerac- tinians (solitary such as Balanophyllia europaea or colonial such as Cladocora coespitosa), feeding by inserting the probos- cis inside the stomodeum and possibly sucking out the pre- digested content. Sex change is assumed to occur when shell length reaches 3–4 mm. The constancy in the differences in size, ecology and reproductive biology, and the absence of observed intermediates between the two forms was striking and suggested the analysis of their specific status by other independent markers. We had much difficulty in assaying coralliophilines by standard allozyme electrophoresis, since we obtained very weak staining of enzymes or no evidence of activity at all. Similar problems have been encountered by other workers RESEARCH NOTES Contrasting morphological and molecular variation in Coralliophila meyendorffii (Muricidae, Coralliophilinae) Marco Oliverio 1 and Paolo Mariottini 2 1 Dipartimento di Biologia Animale e dell’Uomo, “La Sapienza” University, Viale dell’Università 32, I-00185 Roma, Italia. E-mail: marco.oliverio@uniroma1.it 2 Dipartimento di Biologia, “RomaTre” University. Viale Marconi 446, I-00146 Roma, Italia. E-mail: mariotpa@uniroma3.it Figures 1–4. Morphological variation in the Coralliophila meyendorfii complex. Scale bar, 10 mm. Figure 1. A and B S. Pietro Is. on Anemo- nia sulcata. Figure 2. A and B S. Pietro Is. on Balanophyllia europaea. Scale bar, 5 mm. Figure 3. A and B Castro Marina, on Anemonia sulcata. Scale bar, 10 mm. Figure 4. A and B Castro Marina, on Cladocora coespitosa. Scale bar, 10 mm.