(Semper, 1868)
P. nigra is a dark brown sea cucumber bearing brown tentacles with a dark stripe on the outer side. It is a large species with 15 tentacles. The spicules are anchors with knobs at their vertex, unbranched bases and small, branched miliary bodies (P. nigra spicules[/l]). P. nigra may be found on [l][m]Glossary[/m][r]Reef[/r]reefs, on the reef flat.