Polydorid species (Polychaeta : Spionidae) in Japan, with descriptions of morphology, ecology and burrow structure. 2. Non-boring species

A total of 11 polydorid species of the family Spionidae were extracted from non-calcareous substrata from Japan. The polydorids were: one Polydora sp. , Polydora cornuta; three Dipolydora spp, Dipolydora quadrilobata, D. carda lia, D. socialis; one Carazziella sp., Carazziella spongilla; one Boccardie lla sp., Boccardiella hamata; two Boccardia spp., Boccardia perata, B. prob oscidea; three Pseudopolydora spp., Pseudopolydora cf. kempi, P. antennata, P. paucibranchiata. All inhabited mud deposits including mud in crevices o f calcareous substrata, sponge and sandstone rocks, and were never found in self-escavated burrows in calcareous substrata. This study attempts to sum marize and discuss the taxonomic, morphological, and behavioural characteri stics of these non-boring species inhabiting Japanese waters and to compare them with the previously known boring species. The 11 non-boring species b elonged to six genera. Thus their taxonomic and morphological variability w as higher than those of boring species, which belonged only to three genera . A generic overview suggests that some genera contain many species capable of boring and others contain many species incapable of boring. Branchial b lood vessels were thick and conspicuous in non-boring species. Moreover, th ey showed high crawling activity and a strong, vigorous palp movement. Thes e observations suggest a possible link between boring activity and the morp hology and behaviour in polydorids. In addition, Polydora cornuta, Dipolydo ra quadrilobata, D. cardalia, D. socialis, Boccardia perata and Pseudopolyd ora cf. kempi are new to Japan.