XXIV.—The Fresh-water and Terrestrial Mollusca of Northern Asia

Abstract

The following account deals with the systematics and distribution of the fresh-water and terrestrial molluscs of Siberia and Northern Kazakstan. During the open seasons of the years 1932 and 1933 journeys were made through that country, typical areas in several of the great natural regions were examined in some detail, and extensive collections were made. The object of this expedition was to obtain fresh and accurate information regarding the constitution and distribution of the molluscan fauna. During the past one hundred years several scientific papers have appeared which refer to the molluscs of this territory, but despite this the knowledge of this group of animals in Northern Asia has remained in a very unsatisfactory state. This has been due to the collections in the past having been made incidentally in the course of other work, and little or no attempt has been made to evaluate the fauna as a whole. The most thorough investigation so far carried out in this region is that of Westerlund (1877), but his paper was published nearly sixty years ago, and the advances in the study of the mollusca since that time make it essential that some revision and extension of the work should be undertaken. The present paper is one contribution toward that end.