沖縄島およびその周囲の離島におけるカイヤドリヒドラ類(ヒドロ虫綱, 軟クラゲ目)のポリプの地理的分布

Abstract

Distributions of hydropolyps of bivalve-inhabiting hydrozoans were studied around Okinawa Island and its adjacent islands between 1990 and 2004. Eugymnanthea japonica was associated with the bivalves of Barbatia virescens, Crassostrea gigas, C. sp. and Dendrostrea sandvichensis, and was found from six of 20 stations surveyed, both on the western and eastern coasts of Okinawa Island (one station was on Yagaji Island, near the westen coast). Although the mature medusae of Eutima japonica, another member of this hydrozoan group, were recently found from Okinawa Island, hydropolyps of this species were not found.