Notes on the collection of land-mollusca made by Dr. E . Jacobson on the Islands of Simalur and Babi in 1913, with descriptions of new species and races

I am indebted to the authorities of the Leiden Museum for the opportunity of examining and reporting on the large collection made by the late Dr. E. Jacobson on Simalur island and on its smaller satellite Pulau Babi, in 1913, between the months of January and September. The collection is large enough to enable one to study good series of a number of the forms collected, and to justify the naming of several new races. Some new forms had already been named by Dr. C. A. van der Willigen, who studied the collection several years ago. Whenever possible I adopted Dr. van der Willigen's MS names. It is now possible to compare the faunas of Simalur Is., Nias Is., and Enggano Is., but the fauna of the Mentawi islands is unfortunately still very imperfectly known. I have to thank Dr. L. A. W. C. Venmans for figures of the radulae of several species of which he has kindly made preparations, and Mrs. van der Feen (née van Benthem Jutting) for helpful notes. Also my thanks are due to Dr. van Regteren Altena for the trouble he has taken in making the collection available to me. And lastly I must record my indebtedness to the late Mr. Wilkins of the British Museum (Natural History) for the three figures of new forms described below, and for other help which he always was ready to give. Large though the collection is, I do not doubt that future collecting will add other forms to the Simalur list. Any conclusions, therefore, made from the present list are subject to reservations. The type-specimens of the new forms described below are in the Leiden Museum.