The shells collected by Dr. ten Kate, are from localities which were still very imperfectly or not at all explored. To the latter category belongs the isle of Soemba, which has furnished a few very fine and interesting new species. Other species, though known to science, are remarkable for the novelty of their localities or because the habitat was not yet ascertained. Considering that Dr. ten Kate travelled in behalf of the Dutch Geographical Society and that his chief occupations consisted of geographical and ethnological investigations, the number of species presented to the Leyden Museum must be called important. With respect to the literature, I must remark, that I have usually cited: for the Landshells, the second volume of the Zoological Series of »Die preussische Expedition nach Ost-Asien”, by Prof. Ed. von Martens, Berlin, 1867, and for the Melanidae and Neritinae, the monographs of these genera published by Dr. Brot and by Prof. von Martens in the second edition of Martini Chemnitz' »Systematisches Conchylien-Cabinet”; these works give a full account of the synonyms.