Length, 3 mm; diameter, 1 mm. Shell: elongate-conic, slender, distorted; with a prominent granular spiral keel on each whorl; white. Spire: protoconch of one and one-half smooth, glistening whorls; teleoconch of three flat-sided whorls; suture wide, shallow. Sculpture: a prominent beaded spiral keel on each whorl with a lesser spiral below, the two keels joined by fine axial ribs; base of last whorl with three smooth spiral keels. Aperture: subcircular; outer lip with a heavy varix. Color: white. Worn shells are rarely found in drift and to depths of 20 m, but nothing is known of the habits of living animals.
P. miranda has been recorded from the Indian Ocean and southern Japan.

As Rissoina eucosmia:
Shell small, falcate, semitranslucent. Nuclear whorls a little more than one, smooth, well rounded. Postnuclear whorls high between the sutures, strongly shouldered at the summit, marked on the anterior half by strong, comma-shaped axial ribs, which are truncated posteriorly, tapering gently anteriorly and are lost before they reach the middle of the whorl. Of these ribs, 12 occur upon the first, 14 upon the second, 16 upon the third, and 18upon the fourth and penultimate turn. In addition to these axial ribs the whorls are marked between the sutures by a smooth spiral cord, the posterior border of which marks the space between the sutures on the later turns. Sutures strongly channeled. Periphery of the last whorl marked by a strong spiral cord. Base moderately long, marked by two, equal and equally spaced, spiral cords, of which the last encircles the insertion of the columella. Aperture oval; outer lip thick, with a brown band immediately posterior to the spiral keel; inner lip very thick and appressed to the attenuated base; parietal wall covered by a moderately thick callus which renders the peritreme complete.
The type, Cat. No. 250395, U.S.N.M., comes from Pert Alfred (Coll. No. 1268). It has five and a half postnuclear whorls, and measures: Length, 2.8 mm.; diameter, 1.1 mm.

3.2mm. Solid, glossy, semitranslucent, elongate-conic; smooth protoconch of about 2.5 whorls. Spire whorls have spiral row of large tubercles at periphery, 4 smooth spiral cords below periphery of last whorl. White. Habitat: parasitic upon brittle stars. Distribution: GO.