Contributions to West European Cavibelonia (Mollusca, Solenogastres) with two new species

New records of Solenogastres Cavibelonia from French and Spanish coasts, belonging to the West European Atlantic fauna, are presented. They include four species classified within different families of the order Cavibelonia. Two of them are new to science: Simrothiella vasconiensis n. sp. from the southeastern Bay of Biscay and Alexandromenia gulaglandulata n. sp. from the West European basin. The finding of Pararrhopalia pruvoti Simroth, 1893, from off Galicia (Spain) significantly enlarges its geographic range, and the record of Dorymenia sarsii (Koren & Danielssen, 1877) from the southeastern Bay of Biscay bridges a former gap in distribution. These records improve our fragmented knowledge on the biodiversity of Solenogastres of the Northeast Atlantic fauna.