Siphonosoma vastum (Selenka & Bülow)
Figs. 2 C, 3A
Siphonosoma vastum Cutler, 1994: 47, 55, fig. 11 (for complete synonymy).
Material examined. One specimen (NMNS-4099-008), Shiaoliuchiu (22°20.25' N, 120°21.48' E), Pingtung County, lower intertidal shell sand, coll. H.-T. Hung, 3 July 2003.
Remarks. This species is easily separated from congeners by the presence of numerous caecae on the rectum (Cutler 1994: 47, fig. 11). Another peculiar feature is its long introvert with dark claw-shaped hooks in rings (Fig. 3A). It is known to widespread in Indo-West Pacific tropical and subtropical waters. The finding of this species in Taiwanese waters is not unexpected.