(Phascolosoma) scolops (Selenka and de Man, 1883)

Acd, 2000, Sipuncula from Hainan Island (China), Journal of Natural History 34, pp. 2187-2207 : 2198

Phascolosoma (Phascolosoma) scolops (Selenka and de Man, 1883)

Material. Lingchang , 7 April 1992, four specimens ; Lingchang , 10 April 1992, three specimens ; Lingchang , 11 April 1992, four specimens ; Shalao , 4 April 1992, one specimen ; Xincun , 26 March 1992, six specimens ; Xincun , 27 March 1992, one specimen ; Yezhu Island. Yalong Bay , 20 March 1992, one specimen ; Yezhu Island , North side, 26 March 1992, one specimen ; Yezhu Island , 26 March 1992, one specimen ; Yezhu Island , 27 March 1992, three specimens .

Description. Trunk 4±20 mm long with a mean value of 15 mm. Introvert 4±27 mm long with a mean value of 12.5 mm. Introvert/trunk ratios are variable. Small spots over the dorsal part of the introvert. Papillae, distributed over the entire trunk, are larger, more pointed and densely packed at both ends. From 12 to 25 rings of hooks which are 25±75 m m in height. Their shape is variable, sometimes with a hump-like secondary tooth on its concave side. Internally, a distinctly visible triangle in the convex portion and a clear streak are well delimited (®gure 6a±f). Longitudinal musculature in bands and four retractors which in some contracted specimens appear as only two retractors with one and two basal roots, respectively. Two nephridia, 30±75% the trunk length, attached to the body wall for about 30±65% of their length, with most specimens exhibiting mean values of attachment surface.

Discussion. Despite the observation of the hooks, which helped us in its identi- ®cation, this species (together with P. (P.) nigrescens Keferstein, 1865 ) has turned out to display great variability with regards to these cuticular structures. Thus, both the width of the clear streak and the height of the hooks are features very variable across all the specimens of this large collection (they even surpass those ®gures compiled by Cutler (1994) in one large specimen).

Its distribution in the Indian Ocean (including the Red Sea) and Western Paci®c