Clanculus plebejus (Philippi, 1851)
Description: Shell small with rounded whorls, height less than width. Sculptured with polished spiral ribs, 2-3 on penultimate whorl, 4-5 on body whorl above periphery; usually some ribs beaded, and with finer ribs between. Microscopic oblique lamellae present between ribs. Basal margin rounded, with a double rib in adult shells; 5-9 narrow ribs on base. Interior of aperture with external sculpture showing through. Inner margin of outer lip thickened. Base of columella and inside of outer lip denticulate in mature shells. Umbilicus open, with about five beads around margin in mature shells. External colour mottled brown. Interior nacreous silver or green; umbilicus, columella and outer lip white.
Size: Up to 9 mm high, 11 mm wide.
Distribution: Endemic to Australia; Sydney, NSW, to south-western WA, including Tas.
Habitat: Under stones on sheltered rocky shores, low tide level and below.
Comparison: This species is similar to Eurytrochus strangei with the distinguishing features being; height less than width; some ribs beaded rather than all ribs smooth; columella all white rather than green at base.
Figs. 1,2: Huskisson, Jervis Bay, NSW (C.349779)