Nouvelles signalisations de Mollusques (Prosobranches et Bivalves) dans le Bassin d'Arcachon.

New records of Molluscs (Prosobranch Gastropods ancl Bivalves) from the Bay of Arcachon. The occurrence of two species of Prosobranch Gastropocls (Gib/J/I/a a/hida, Hya/a vitreal and four Bivalves (Thyasira/7e-l"l/osa, Lucinol11a borealis, \lascolliellai~ffi'eysiana, Sphenia hinghw1Ii) is reported for the tirst time in the Bay of Arcachon. The re cent expansion of Cyclope nerilea ancl Macoma ha/lhica in the Bay is a lso discussed.