Mauia angusta (Suter). (Plate 61, figs. 4, 13.)

Shell small, fusiform. Spire strongly gradate, not quite equal in height to aperture. Whorls broad and low, with a concave shoulder, below which body-whorl is slightly convex then contracted; anterior fasciole strongly developed, bounded above by prominent ridge, and with another broader ridge a short distance above lower boundary. Suture undulating. Sculpture of 7 long strong tubercles, which extend longitudinally as axial ribs almost to basal fasciole below, and often, though weakly, to suture above. Aperture oblong, angled above, with deep anterior notch. Outer lip thin, straight. Columella with 4 rather weak folds, anterior two close together.

Holotype and lectotype in collection of New Zealand Geological Survey.

Locality.—164, greensand, Kakahu.

The type specimen of Galeodes angusta is an internal cast, but it clearly belongs to the same species as a number of strongly ribbed Volutes which Suter classed along with two other species under his Lapparia hebes (Hutton).

Satisfactory generic placing of this shell is rather difficult. It probably represents the ancestral type of such shells as Mauia, in which the suture in neanic whorls is below the periphery, and which have a similar four-plaited columella, deep anterior notch, and prominent fasciole with strong ridge bounding it above, and another strong central ridge with concave space between. It also resembles Aldithoe, from the typical species of which it differs not only greatly in size but also in the small nucleus and strongly-ridged fasciole. M. angusta may, indeed, be an ancestor of Alcithoe; the highly specialized siphonal fasciole probably indicates that it is not on the direct line, but marks a gerontism that culminates in such forms as M. maoriana, and M. huttoni.

M. angusta, as perceived by Suter, closely resembles Lapparia, but the fasciole is slightly more specialized, there is no spiral sculpture, and the axials have developed along a different line, having become strong and tubercular, while those of Lapparia develop into spines something like those of M. maoriana. Unfortunately, none of the specimens shows a complete apex.

What is probably a related species, though much more slender, occurs at locality 759, Castle Hill shaft, Kaitangata. The single specimen is incomplete, and is mostly an internal cast, so one cannot be certain about it.

Mauia biconica (Suter). (Plate 61, fig. 15.)

• Galeodes biconica Suter, N.Z. Geol. Surv. Pal. Bull. 5, p. 18, pl. 11, fig. 20.

• Fulgoraria (Alcithoe) biconica Suter, N.Z. Geol. Surv. Pal. Bull. 5, p. 39, pl. 5, figs. 5, 6.

Curiously enough, Suter gave the same specific name to the two shells listed above. The one which he called Galeodes biconica has 4 strong plaits on the pillar and so is certainly not a Galeodes (= Melongena); it agrees, however, in all particulars except size with the type of Fulgoraria biconica. Galeodes biconica has page priority, so the small shell becomes the type of the species. One of Suter's plesiotypes of Lapparia hebes (Hutton) is a M. biconica (Suter, 1917, p. 41, pl. 12, fig. 11.) Sometimes it is difficult to decide whether young shells are M. biconica or M. maoriana, as the latter passes through a stage represented by the former.

Localities.—Greensand, Kakahu (type); greensand, Waihao Downs; Hampden.

Mauia curvispina n. sp. (Plate 69, fig. 13.)

Shell large, solid. Spire low, conic, one-quarter height of aperture. Spire-whorls slightly concave; body-whorl with long steep slightly convex shoulder, which is strongly tubercular on the periphery, below which whorl contracts very slowly at first then rather quickly to a huge fasciole bounded above by high narrow ridge and traversed by strong median rounded ridge. Sculpture: periphery armed with 10 tubercles, at first low and sharp, but increasing rapidly in strength so that later ones are long and strongly curved posteriorly. Suture undulating, situated a little above line of tubercles and on last half-whorl filled with callus. Aperture fairly large, very deeply and rather narrowly notched below. Outer lip broken but apparently rounded, not reflexed, and strongly convex. Columella with 4 high, narrow, spaced plaits. Inner lip fairly well spread as a thin glaze, forming a moderate pad on the parietal wall.

Holotype in collection of New Zealand Geological Survey, deposited by Mr. R. S. Allan.

Height, 72 mm.; diameter, 45 mm.

Locality.—Greensand, Waihao Downs.

This species represents an advance from M. biconica, marked by convexity of the body-whorl, and the development of long recurved spines.

Mauia maoriana (Suter). (Plate 61, fig. 9; and text-fig. 2a.)

The resistant matrix having been cleared from the aperture of the holotype, the columella displays 4 strong oblique folds, the anterior one weaker than the others. This with the deep anterior notch shows that the shell is a Volute, not a Galeodes (= Melongena). A description of the ontogeny and relationship to Mauia biconica (Suter) is given above (p. 262). The embracing, rounded body-whorl, calloused suture, and anteriorly placed tubercles are all gerontic features.

Locality.—164, greensand, Kakahu.

Mauia huttoni (Suter). (Plate 61, fig. 8.)

The shell (fig. 2b) listed from Mount Harris as Fulgoraria biconica (Suter, 1921, p. 64) is not that species, for it has a more contracted convex body and a longer neck; but it agrees exactly with the apex of well-preserved specimens of Mauia huttoni, and can be regarded with practical certainty as the young of that species. The preservation and adhering matrix are not like those of Mount Harris, but are identical with some of the fossils from Trelissick Basin, locality 451a, Pareora beds, junction of Porter and Thomas Rivers. Although the locality-label now reads 475, the 7 has been put on with different ink at a much later date over an original 5. Locality 455 was supposed to be from the Triassic of Okuku, but in a manuscript copy of fossiliferous locality descriptions written by McKay the following note appears: “This collection is wrongly numbered, as 455 is a numerous collection of Miocene fossils either from Pareora River Valley or the Thomas River, Trelissick Basin.”

Locality.—Broken River, Trelissick Basin.