Genus Siphonosoma Linnaeus

Remarks. The genus Siphonosoma differs from the genera Sipunculus and Xenosiphon Fisher, by the presence of anastomosing circular and longitudinal muscles (Cutler 1994: 26, fig. 3) and from Siphonomecus Fisher, by having four introvert retractor muscles (RMs), respectively. The present study reports two new records, Siphonosoma funafuti (Shipley) and S. vastum (Selenka & Bülow) from Taiwan.