On the presence of an Asiatic species of Corbicula in France and Portugal A bivalve species of the genus Corbicula has recently been dredged from the estuaries of the Dordogne, France (accompanied by various species of Pisidium), and of the Tagus, Portugal. After careful examination of the shells we think that these probably belong to Corbicula manilensis (Philippi, 1849), a synonym of C. fluminalis (Müller, 1774), which has also invaded North America. Although living in the same type of substrate with mainly sand and mud, the two populations show marked differences. The Corbicula from the Tagus reach 41 mm, colonize fresh water but tolerate a salinity of ca. 30 per thousand, and the animal does not exhibit any pigment at all, while specimens from the Dordogne do not grow beyond 20 mm, exclusively live in fresh water, and show traces of pigment around the siphons.