A NEW SPECIES OF SACCOCIRRUS (ARCHIANNELIDA) IN JAPAN

Abstract

Begins: From a beach sand sample collected at Kashima Islet in Tanabe Bay, Wakayama Prefecture, Japan, in June 1972, the writer happened to find a lot of specimens of an archiannelid belonging to the genus Saccocirrus Bobretzky. The worm, comparatively smaller than S. major Pierantoni which is the only species of the genus previously recorded in Japan (Uchida, 1933), seemed closely related to S. eroticus Gray recently described from the west coast of North America, because only these two forms had the ciliated ventral groove among the eleven species of the genus. Microscopic observations have revealed, however, that the animal in question is distinguishable from S. eroticus in some diagnostic characters. So the present paper is prepared to describe it as a new species.