Sipunculus (Sipunculus) phalloides phalloides Pallas, 1774
One of the large worms in the genus Sipunculus, this species is found in warm shallow waters. When alive, the worm has a pink coloration that is usually retained after fixation.
(From Ditadi, 1982 and Cutler, 1994)
External anatomy
Introvert shorter than the trunk. Triangular papillae with blunt ends, arranged irregularly over the surface.
Trunk is cylindrical measuring 150-254 mm in length. Trunk diameter/length ratio averages 1:13. The surface of the trunk is divided into a large number of small rectangles by the intersection of the longitudinal and circular muscles.
Tentacular crown consists of two large dorsal lobes and two smaller ventral lobes. Both pairs are leaf shaped with foliated borders.
Internal anatomy
35-41 longitudinal muscle bands (LMBs). The LMBs do not divide in the glans region.
Nephridia are unattached, extending less than 25% of the trunk length and opening5-10% of the trunk length anterior to the anus. The nephridiopores open between LMBs 4 and 8.
Brain is bilobed with digitate processes.
Two pairs of retractor muscles arise at the same level. The ventral pair originates in LMBs 1or 2 and spreads over two to six bands, and the dorsal pair starts on LMBs 12-16 and spreads over two to six bands.
Spindle muscle is weakly developed.
Caribbean, Brazil, eastern Pacific (from Costa Rica to Galápagos Island). One specimen collected at 15 m off Ivory Coast (Cutler, 1994).
This is an intertidal and shallow water species (Cutler, 1994).