"The Meridional Marinula,""
apparently so called from the variceal rib down the centre of the back of the body whorl. Oblong-ovate, thin, transparent, imperforate; light-horn colour, peristome and columella white; axially striate, otherwise smooth; usually a varix, the remains of an old mouth, in the centre of the back of the body whorl; spire acuminate; protoconch papillate; whorls seven, slightly convex; suture impressed; base rounded; mouth vertical, narrowly ovate, as long as the spire; outer lip slightly reflected; inner lip with three folds. Height 8 diam. 4 mm. Port Adelaide River, under shrubby-samphire, just above high-water mark; not uncommon. (Type locality—Port Adelaide River, in swamps.)