ZOOLOGICAL RESULTS OF A TOUR IN THE FAR EAST. 
THE MOLIvUSCA OF LAKE BIWA, JAPAN. 
(Plate in.) 
By N. Annandale, D.Sc, F.A.S.B. {Zoological Survey of India). 
A pamphlet on the Mollusca of Lake Biwa, unfortunately for European readers 
in Japanese, has recently been published by the Fishery Department of the Shiga 
Prefecture, which maintains a well-equipped station near Hikone on the eastern side 
of the lake. This pamphlet deals with the molluscs primarily from an economic point 
of view, several species (notably Corbicula viola) having considerable value as food, 
while others (in particular Hyriopsis schlegeli) are sought mainly on account of their 
pearls; but it also contains valuable information as to the distribution of various 
species in the lake and its immediate vicinity, and good photographs of shells are 
reproduced as well as a valuable map illustrating the local and bathymetric range of 
commercially useful genera. . I have made use of extracts, which have been trans- 
lated for me by Dr. T. Kawamura, as well as of the figures and map. 
The pamphlet recognises only 21 species (8 of gastropods and 13 of lamelli- 
branchs) as occurring in Lake Biwa and the surrounding pools, ditches and irrigated 
rice-fields. In the present paper 33 species are accepted as distinct, 15 of gastropods 
and 18 of lamellibranchs. 
The reason for this difference is twofold — in the first place it is owing to the 
discovery of species either new to science or not recorded hitherto from the lake, and 
secondly to the fact that the anonymous authors of the Japanese memoir have in 
some cases paid no attention to differences in the shells that recent authorities regard 
as of specific importance. Mr. H. B. Preston ^ has described the new species dis- 
covered in the course of m}^ own investigations or obtained by Dr. Kawamura, while 
Haas's as yet incomplete monograph of the Unionidae ^ has proved of great value in 
the identification of shells of that family. 
The new species are either from deep water, in which they were obtained by 
means of a small dredge and a D-net on the bottom, or else from the lower surface of 
stones near the margin — a type of environment very profitable to the collector of 
Mollusca in lakes. 
The following is a complete list of the known Mollusca of Lake Biwa according 
to the nomenclature accepted in this paper ; the species whose names are marked 
with an asterisk are represented in my collection or in that of the late Dr. John 
1 Ann. Mag. Naf. Hist. (8) XVII, pp. 159-163 (1916). 
^ Die Unioniden in Chemnitz's Syst. Conch. Cab. (new. edit.) IX, ii, 2 (1911 — ). 
