The ossicles (microscopic calcareous spike-like structures that support the body wall) are large and shaped like anchors and are used in locomotion; they can be as long as 2 mm.

They are about 2.5 cm (1 in) long when extended and have a short stem and a feather-like blade with thirty to forty pairs of pinnules.

[7] Two previously unknown triterpene holostane glycosides have been isolated from S. maculata; one has moderate activity against HeLa tumour cells while the other is inactive.

[8] Naturalist Gerald Durrell's 1977 observations of this creature were made when he was snorkeling in shallow water in Mauritius: "At first, I could not believe that these weird objects were alive.

I thought they must be strange, dead strands of some deep-sea seaweed now washed into the shallows by the tide, to roll and undulate helplessly on the sand to the small movements of the sea.