Shell low to fairly high, right side somewhat bulging, apex usually worn. Radial ribs well spaced and often angular, projecting at margin, unequal in size, totalling about 40-50 in typical adults, juveniles with as few as 22; sometimes (form albofasciata Krauss, 1848) fused into 9-15 broad, flat rays, forking to¬wards the margin. Brownish-grey with paler grey or fawn ribs; interior brownish, with a large white central callus deposit, margins brownish-black with white radial lines. Juveniles show iridescent blue-green flecks externally. Maximum length 34 mm. RANGE; Zululand to Table Bay. NOTES: A variable species with a number of synonyms. Blue-flecked juveniles were once differentiated as 5. cyaneomaculata Sowerby, 1906. Previously known as S. deflexa Helbling in Born, 1778, an unidentifiable species.
S. concinna lives in groups on exposed rocks between high-water springs and low-water neaps, forming a distinct home-scar. It is said to feed on black lichens and probably other encrusting plants as well.