Polydorid species (Polychaeta : Spionidae) in Japan, with descriptions of morphology, ecology and burrow structure. 1. Boring species

A total of 13 boring species of spionid polychaetes were extracted from 28 different calcareous substrata (i.e. mollusc shells, coralline algae and ba rnacle tests) from Japan. The spionids were: seven Polydora spp.: Polydora brevipalpa, P. websteri, P. curiosa, P. uncinata, P. aura, P. glycymerica P olydora sp.; five Dipolydora spp.: Dipolydora concharum, D. bidentata, D. a lborectalis, D. giardi, D. armata; and one Carazziella sp.: Carazziella rei shi. All of them inhabited self-excavated burrows in living and/or migrator y calcareous substrata and they were never found from soft sediments. Burro w structures were species-specific. The Polydora species basically excavate d simple U-shaped burrows, while the Dipolydora species excavated more vari ed, distinct burrows. The boring activity seemed species-specific among pol ydorids. This study attempts to summarize and discuss the biological charac teristics of these boring species inhabiting Japan. In addition, P. curiosa , P. glycymerica, Polydora sp., D. giardi and C. reishi are new to Japan.