Body cylindrical and elongated, with orange markings on the head, a dark orangish brown pattern of markings on the back and orange to yellow rectangular markings on the white undercolor of midbody and belly. Two orange to yellow squares outlined in black behind the eyes (S. annularis).
Size up to 9 cm.
Inhabit deep reefs and rocky areas, down to 70 m, but rare in water less than 30 m. Occurs often in pairs, rest on bottom near entrances of protective recesses. Synchronously hermaphroditic.
Occasional South Florida, Bahamas and Caribbean.