Preliminary Notes on Molluscan Assemblages of the Submarine Banks Around the Izu Islands

Abstract

It is well known that there are several submarine banks along the submerged rise which extends southwestward from the southern tip of Izu Peninsula, central Honshu. Small islands such as Toshima, Niijima, Shikine, and Kozu, with several other islets, lie on this rise. These, together with a few other islands situated farther south; are called the Izu Islands. They are linked by a volcanic system, and there is a considerable number of such banks in the neighborhood. A few papers concerned with hydrographical, bathymetrical, and faunistic characteristics of these submarine banks have been prepared by Suzuki and Sato (1944) , Niino (1935, 1952, 1955), and Shirai (1958). On the basis of these works, together with information furnished by the present author, Horikoshi (1957) discussed the topographical peculiarity in relation to the general molluscan fauna on these banks.