ALBERT

Description: Part I of this monograph has been published in volume 10 of this Journal, pp. 241—320, 1938. Preparing this second part I met with the help and assistance from many persons and institutes again, for which I express my most cordial thanks here. The figures illustrating this paper have been drawn once more by Mr. L. P. Pouderoyen, while the „Zoologisch Insulinde Fonds” supplied the cost of these illustrations.

Description: Part III of this monograph (by Dr. F. A. Schilder) was published in volume 12 of this Journal, pp. 171—194, 1941. The fourth part deals with the families which can be summarised as Tonnacea (= Doliacea Thiele). They contain 31 species, two of which are new to science. The manuscript was already completed in the summer of 1940, but there was no earlier occasion for publication.

Description: Part III of this monograph (by Dr. F. A. Schilder) was published in volume 12 of this Journal, pp. 171\xe2\x80\x94194, 1941.\nThe fourth part deals with the families which can be summarised as Tonnacea (= Doliacea Thiele). They contain 31 species, two of which are new to science. The manuscript was already completed in the summer of 1940, but there was no earlier occasion for publication.

Description: Part I of this monograph has been published in volume 10 of this Journal, pp. 241\xe2\x80\x94320, 1938. Preparing this second part I met with the help and assistance from many persons and institutes again, for which I express my most cordial thanks here.\nThe figures illustrating this paper have been drawn once more by Mr. L. P. Pouderoyen, while the \xe2\x80\x9eZoologisch Insulinde Fonds\xe2\x80\x9d supplied the cost of these illustrations.

Description: INTRODUCTION\nEngaged in the study of fossil shells belonging to Thiele\'s sectio Cerithideopsilla of the genus Cerithidea Swainson and deriving from plio-pleistocene beds in East Java, I failed to find a satisfying account on the recent species of this group. Therefore I resolved to examine as large a material as possible myself in order to settle the value of the different species and varieties that have been described in literature.\nThis investigation led me to the conclusion that even after the inspection of some 1950 specimens I cannot speak the final word, as ecological observations seem necessary to test the taxonomic value of the characters used for distinction. But a preliminary order may be established by the following revision of the material available to me, in which I propose to distinguish four species until field observations have thrown more light on the variability of these molluscs 1).\nTryon (1887, pp. 159/160)\xe2\x80\x94with his usual taste for lumping\xe2\x80\x94cites the following synonyms of "Potamides fluviatilis Potiez et Michaud" in his Manual of Conchology: Cerithium microptera Kiener, Cerithium alatum Philippi, Cerithium radix Dufo, Cerithium incisum Hombron et Jacquinot, Cerithium retiferum G. B. Sowerby 2 and Tympanotonos euryptera A.\nAdams M. S., G. B. Sowerby 2.\nJudging from the description (Dufo, 1840, p. 62) Dufo\'s radix seems to be a true Cerithium. My material contained no specimens matching the figure and description of Cerithium retiferum G. B. Sowerby 2 (1855, p. 892, pl. 186 fig. 295) and therefore I shall not discuss this form, which at any rate seems closely related to Cerithidea cingulata (Gmel.). The remaining forms