Etude des protoconques de quelques prosobranches de la région de roscoff

The protoconches of different species of Prosobranches from the Roscoff area are studied with scanning electron microscopy: Rissoidae, Cingula semistriata, Cingula semicostata, Cingulopsis fulgida, Alvania beani, Alvania crassa, Alvania carinata, Alvania punctura, Alvania zetlandica, Rissoa guerini, Rissoa inconspicua, Rissoa lilacina, Rissoa parva, Risso sarsi, Barleeia rubra; Cerithiopsidae, Cerithiopsis jeffreysi, Cerithiopsis tubercularis, Cerithiopsis metaxae; Triphoridae, Triphora perversa; Buccinidae, Chauvetia brunnea; Turridae, Haedropleura septangularis, Lora rufa, Mangelia coarctata and Mangelia nebula. Based on their protoconch morphology, the development type is indicated for seven species whose reproduction was unknown: Alvania beani, Alvania zetlandica, Rissoa lilacina and Mangelia coarctata have a development with a pelagic phase; Alvania carinata, Chauvetia brunnea and Lora rufa have a direct development or a development with a very short pelagic phase. Among Rissoidae whose planktonic larvae were particularly difficult to identify, the description of the protoconches enables a more reliable diagnosis.