Rissoina angusta: Shell narrowly conical, tall, slender, with whorls longitudinally ribbed and contracted beneath the suture. Colour uniform golden brown. Whorls seven, of which two are nepionic, the last equalling in length the three previous, slightly rounded ; each whorl contracted, the third at midway down, the rest at intervals receding posteriorly, the last at just beneath the suture; sutures sharply sinuate. Sculpture ;—no spiral sculpture is visible, the longitudinal is by sharp, strong, perpendicular ribs, slightly arched, suddenly deflected and almost beaded at the above described contraction, continuous from whorl to whorl, faint upon the last. Aperture perpendicular, ovate, scarcely effuse anteriorly, outer lip sinuate, produced, fortified outside by a slight varix, columella overlaid by a thick callus. Length 3.25, breadth 1 mm.

2.7mm. Thin, glossy, translucent, fusiform, aperture about a fourth of total length, outer lip straight sided, sutures wavy; pointed protoconch of 4 smooth whorls. Sinuous axial ribs narrower than their intervals. White. Habitat: shallow water. Distribution: GO, Mas.