Prosimnia semperi (Weinkauff, 1881)
Description: Shell elongate, with aperture extending along entire shell length. Whole surface sculptured with fine spiral ribs; sometimes with a broad nodulose rib at the shoulder. Upper four-fifths of outer lip folded in, thickened internally and externally, densely lirate on ventral surface with some or all lirations extending onto outer surface of outer lip. Lower fifth of outer lip flared, denticulate on outer edge. Inner lip of aperture smooth except for about six lirae above shoulder. Colour white, fawn, pink or light purple.
Size: Up to 13 mm in length.
Distribution: Indo-West Pacific; in Australia, Exmouth Gulf, WA, to Jervis Bay, NSW.
Habitat: Off Sydney, this species has been recorded on a gorgonian Mopsella ellisi at a depth of 30 m. It takes on the colour of the gorgonian on which it lives (Coleman, 1975). Rare in NSW.
Comparison: The finely ribbed surface and densely lirate outer lip distinguish this species.
Figs. 1,2: Wreck Bay, Jervis Bay, NSW (C.387979)
Copyright Des Beechey 2004