| Some scanning electron microscopy observations have been conducted on different species of Prosobranches from the Roscoff area: Trochidae, Calliostoma zizyphinum, Gibbula magus, Gibbula cineraria, Gibbula tumida, Cantharidus clelandi, Cantharidus exasperatus, Cantharidus montagui, Cantharidus striatus; Skeneidae, Skenea serpuloides, Skenea cutleriana, Skenea nitens; Skeneopsidae, Skeneopsis planorbis. Observed with closer attention are the protoconch and the first juvenile spiralial whorls. The studied Trochidae have a protoconch of about one spiralial whorl; the spire is round, with an oval opening and a fine ornamentation in G. magus and C. striatus, and in G. cineraria, G. tumida, C. clelandi, C. exasperatus and C. montagui, one can notice a dorsal... |
