Peanut worms of the phylum Sipuncula from the Nha Trang Bay (South China Sea) with a key to species Author Adrianov, Andrey V. Author Maiorova, Anastassya S. text Zootaxa 2012 3166 41 58 journal article 45619 10.5281/zenodo.279772 32627594-388c-40b3-8481-0b241b850847 1175-5326 279772 Cloeosiphon aspergillus (de Quatrefages, 1865) ( Fig. 6 C–D) Material. Nha Trang Bay: Mot Island, coral rubble, 7 m , May 2008, 12 specimens; Tre Island , coral rubble, 6 m , Jun 2008, 18 specimens; Tre Island , biofouling, intertidal, Nov 2009, 6 specimens; Mung Island, coral rubble, 12 m , May 2008, 15 specimens; Nok Island, coral rubble, 5 m , 8 specimens ; Diamond Bay: coral rubble, intertidal, Jun 2008, 25 specimens; Nov 2009, 16 specimens; Mar 2010 , 8 specimens. Description. Trunk up to 70 mm long, 4–5 mm wide, light brown or grey, with minute brown papillae, semitransparent; introvert shorter than trunk. Anal shield consists of white rhomboid or polygonal mosaicly arranged, calcareous units, with a dark central pore; caudal shield absent. Introvert protruded through the center of the anal shield; bidentate hooks arranged in rings distally. Longitudinal musculature continuous; retractor muscles originate in the middle of the trunk. Gut with 10 loops. Nephridia are about 70–90% of trunk length, completely attached to the body wall. Discussion. This is the only species of the genus Cloeosiphon , and because of its unique configuration between the anal shield and the introvert by far the most distinctive species of sipunculans. This tropical species is widely distributed in the Indo-West Pacific. In the West Pacific it has been reported from Australia to Hainan Island, inhabiting coral rocks in shallow water.