suturalis: globose; sutural channel about 0.75 mm. wide; outer lip retracted to suture.

prisca: slightly compressed; channel about 1 mm. wide; outer lip concave, noticeably retracted to suture.

compressa: compressed; channel about 0.75 mm. wide; outer lip slightly retracted to suture.

vaughani: often large and strong, globose; spire elevated; sutural channel about 0.5 mm. wide, sometimes less; outer lip not noticeably retracted to suture.

Sulconacca suturalis (Hutton). (Plate 57, fig. 1.)

1877. Lunatia suturalis Hutton, Trans. N.Z. Inst., vol. 9, p. 597, pl. 16, fig. 11.

1915. Ampullina (Megatylotus) suturalis (Hutton) Suter, N.Z. Geol. Surv. Pal. Bull. 3, p. 10.

Shell rather small, globose; spire gradate, a little over half the height of aperture; whorls 5, convex; suture fairly deeply and widely channelled (0.75 mm. wide in a shell of 10 mm.); whorls smooth and polished, with some obsolete microscopic spirals, crossed by very fine growth-lines; aperture semilunar, effuse below; outer lip with a shallow sinus in middle and slightly retracted to suture on upper part of whorl, inclined 20° from vertical; inner lip thin; umbilicus fairly wide but varying somewhat, bounded by a shallow furrow.

Neotype in collection of Mr. R. S. Allan, Dunedin.

Height, 12 mm.; diameter, 10 mm.

Locality.—Greensand, McCullough's Bridge, Waihao River.

Hutton's type, which was stated to be from Waihao (i.e., the greensands), has been lost (Suter, 1915, p. 10). Since several similar species occur at this and other localities (all previously classed A. suturalis), it is therefore important to choose a suitable neotype. Obviously, if there, were no impediment, the specimen used by Suter for his description should be taken, but unfortunately the locality is doubtful. The tablet is labelled “Waihao,” but the form and preservation of the shell, and the matrix within it, were noticed by Mr. Allan to be different from such as are found in the greensand there. Similar shells and matrix occur above the limestone of the Pareora River, at Blue Cliffs and Mount Horrible, so it seems likely that the specimen was from one of these localities and had become mixed with a Waihao collection. Perhaps it is really from the Waihao Valley, but from a horizon above the limestone. Hutton distinctly says his Waihao shells were from the greensand, so unless his actual type can be produced the neotype should be chosen from that bed. His figure is of a globose shell with a low spire, and of large dimensions, and does not look very like a Waihao shell. Indeed, it is more like Suter's specimen, so the error of locality may have crept in before Hutton handled the specimen, and Suter may have actually used the type for his description without knowing it.

Since there are no means of finding out which is the correct solution, and since Hutton gave the locality as “Waihao greensand,” it seems advisable to select a neotype from the several species that occur in that bed. Therefore the specimen from Mr. Allan's collection, figured on Plate 57, fig. 1, is here chosen. We know that Hutton had some specimens from McCullough's Bridge, because he speaks of a small shell with a very strong umbilical ridge. This can be none other than N. haasti.

Sulconacca prisca n. sp. (Plate 57, fig. 2.)

Shell rather small, subglobose, with somewhat flattened sides; spire gradate, about one-half the height of aperture; whorls 5 or 6, with some