Within the RBINS collection of Belgian Recent Invertebrates, most of the approximately 1 million specimens are molluscs. A large proportion of this material comes from former RBINS director Gustave Gilson, who was one of the first Belgian oceanographers. He systematically sampled the North Sea between 1898 and 1939. Of course, his colleagues also brought material back from expeditions to Belgian waters and on land, as they still do today. The collections are classified systematically and include both dry and wet specimens. In the philosophy of the RBINS, reference collections were (and are) built from all corners of the world. Thus we have specimens that scientists collected during many foreign expeditions. The “dry” specimens (shells) in these international collections are housed in 3000 wooden drawers, while the “wet” specimens (whole specimens retaining their internal organs) are contained in 10,000 glass jars. These collections are also classified systematically. Other large collections that were purchased by the institute or that were donated are kept separately. The most famous of these is the Philippe Dautzenberg collection, comprising 40,000 species (7000 of which are fossilised): 4.5 million specimens, in 300,000 lots, classified in 2000 (mostly open top) drawers. There is also the associated library of 8000 publications. This RBINS dataset includes an eminent part of that Dautzenberg shell collection.