The shells, mentioned in the following communication, have come in the possession of the Leyden Museum at various times. Some of them have been acquired long ago, and were labelled with false names; other ones have been presented quite recently to the Museum. Most shells represent already known species; but having previously been recorded from other localities, their habitat might be of some interest. Mr. G. K. Gude has had the kindness of identifying those shells, for which I had no specimens or good figures at my disposal for comparison.