ABSTRACT
Elminius plicatus is the largest species, and is sometimes one inch in basal diameter. The outer surface of this latter species is occasionally much corroded. Elminius, therefore, appears to be strictly a southern genus. Elminius Kingii and modestus represent each other on the American and Australian continents. The terga, in the commoner variety, resemble those of Tetraclita porosa; the spur adjoins the basi-scutal angle of the valve: the articular ridge is moderately prominent, and the furrow moderately deep. Shell conical, with a strong tendency in most of the species to become cylindrical: orifice / generally large. Walls either thin and smooth, or thick and plicated longitudinally. Colours various, pale purple, greenish, white, and, in Elminius plicatus, owing to the exposure of an intermediate lamina of shell, bright orange-yellow. The slope of the basal margin of the tergum towards the spur varies in the present species, in a strictly analogous manner, as it does in Tetraclita porosa.
