(B.) “Rissoina” Group. Aperture semilunar, anteriorly effuse, or channelled. 12. Shell solid, elongate, with strong sculpture (generally strong axial riblets crossed by fine spirals, but the latter may be absent); protoconch small, dome-shaped; whorls convex; aperture obliquely oval, channelled below and above, peristome continuous, thickened. Rissoina. Type, R. inca D'Orb. 13. Shell thin, white and highly polished; shell apparently smooth, sculpture very inconspicuous (very fine spiral grooves only, sometimes over the whole surface, sometimes only a few prominent grooves on the base); protoconch minute, flattened; whorls nearly flat; aperture pear-shaped, often truncated below, peristome continuous, outer lip moderately thin, blunt, but reinforced by an external varix. Nozeba. Type, N. emarginata (Hutt.). 14. Shell thin or solid; smooth (rarely with microscopic spiral grooves); protoconch minute, globose; whorls flattened to convex; aperture pyriform or ovate, peristome continuous, hardly thickened. Dardanula. Type, D. olivacea (Hutt.). (C.) Skenella. Shell depressed, orbicular, umbilicated. 16. Shell depressed, umbilicated; smooth; protoconch flatly convex, rather large; whorls convex; aperture large, subcircular. Skenella. Type, S. georgiana Pfr. Of the above genera, Merelina, Onoba, Subonoba, Anabathron, Amphithalamus, and Skenella are as yet unrepresented in the New Zealand Tertiary, while Haurakia, Lironoba, Notosetia, and Epigrus are here recorded for the first time. The best-represented genus is Estea, with five species; then Linemera, with four. Descriptions of the new species are appended, also notes on the other recorded species; to facilitate identification a key to the fossil genera and species is also appended. The thanks of the author are due to Mr. J. Marwick, of the New Zealand Geological Survey, for the drawing of the figure for Estea polysulcata. Haurakia mixta n. sp. (Fig. 1.) Shell minute, ovate, axially costate. Protoconch blunt, of about 1·½ smooth conical whorls; shell-whorls 2, flattish; body-whorl subangled at periphery, base rounded. About 19 flatly rounded axial ribs on last whorl, interstices generally narrower; ribs pass from suture to suture on spire-whorls but suddenly diminish on reaching periphery of body-whorl and rapidly die out just below it. A strong spiral groove crosses ribs just below suture, but otherwise there is apparently no spiral sculpture in interstices or on base. Spire conical, a little higher than aperture, outlines almost straight. Suture inconspicuous. Aperture squarely ovate, subangled above, flattened below. Peristome nearly continuous, sharp. Columella vertical, subtruncate at base. Imperforate. Height, 1·2 mm.; diameter, 0·7 mm.; height of aperture, 0·5 mm. Type, from Castlecliff, in the author's collection. The species has analogy with H. hamiltoni (Sut.) and H. huttoni (Sut.), being in some respects intermediate between them. It is probably juvenile, but is distinctly characterized by its flattish whorls, squat form, and infrasutural groove.