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Volume 55, 1924
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Key to Species.

Carinacca.

  • (a.) Suture impressed, not tangential.

  •   

    haasti: very small; no funicle, huge basal limb.

  • (b.) Suture tangential.

  •   

    waihaoensis: moderate size, broadly ovate; large basal limb, very wide umbilicus, slight funicle coalescing with parietal callus.

  •   allani: moderate size, ovate; large basal limb, large umbilicus, slight coalescing funicle.

Magnatica.

  • sutherlandi: fairly large, broadly ovate; weak basal limb, moderate umbilicus, funicular ridge separated from callus.

  • approximata: fairly large; obsolete basal limb, rather small but open umbilicus, funicular ridge present but weak, a groove from umbilicus across callus.

  • suteri: large, broadly ovate to oval; obsolete basal limb; umbilicus variable, never very large; traces of funicular ridge.

  • nuda: small, broadly ovate; obsolete basal limb; umbilicus fairly large, funicular ridge obsolete.

Natica (Carinacca) waihaoensis (Suter). (Plate 56, fig. 7.)

1917. Ampullina waihaoensis Suter, N.Z. Geol. Surv. Pal. Bull. 5, p. 11, pl. 11, fig. 10.

As Suter's type specimen was imperfect, he did not note the slight thickening of the umbilical wall on the apertural side. In some specimens this feature is quite well marked, and evidently corresponds to the funicle of Natica s. str.

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

Natica (Carinacca) haasti n. sp. (Plate 56, fig. 8.)

Shell small, broadly oval; spire low, about one-third height of aperture; whorls 4; protoconch with moderate nucleus; surface with fine growth-lines, suture impressed not channelled; aperture broadly semilunar; outer lip straight, slightly retracted to suture, inclined about 30° from vertical; inner lip with thin parietal callus not invading umbilicus, which is relatively large and bounded by very strong broad limb which forms prominent thickening at anterior corner of aperture.

Type in collection of Mr. R. S. Allan.

Height, 7 mm.; diameter, 8 mm.

Localities.—McCullough's Bridge, Waihao; Hampden (one specimen is 13 mm. in height = Ampullina suturalis of Marshall, 1923, p. 117).

Natica (Carinacca) allani n. sp. (Plate 56, fig. 4.)

Shell small, ovate; spire less than one-third height of aperture, with almost straight outlines; protoconch of three and a half smooth whorls with minute nucleus, sutures slightly impressed but almost tangential, whorls depressed somewhat below it; aperture semilunar; outer lip straight, strongly retracted to suture, inclined about 25° from vertical; inner lip with short, fairly thick callus on parietal wall, coalescing below with slight funicular thickening; umbilicus widely open, bounded by high wide arm caused by a prominent thickening of anterior corner of apertural margin.

Type in collection of Mr. R. S. Allan.

Height, 19 mm.; diameter, 16.5 mm.

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Localities.—Greensand, Waihao Downs; 164, Greensand above coal-beds, Kakahu, South Canterbury (= P. ovatus and P. huttoni of Suter, 1921, p. 53); 176, sandstone above coal-beds, Black Point, Waitaki Valley (= P. ovatus of Suter, 1921, p. 72); Hampden (= Ampullina waihaoensis of Marshall, 1923, p. 117).

Distinguished from N. waihaoensis by narrower shape and more restricted umbilicus.

Natica (Magnatica) sutherlandi n. sp. (Plate 56, fig. 1.)

Shell large, broadly ovate; spire low and with almost straight outlines; whorls 6, slightly depressed in front of suture; protoconch nucleus very small; suture tangential; surface with sinuous growth-lines, stronger above; aperture semilunar; outer lip concave, strongly retracted to suture, inclined about 30° from vertical; inner lip with moderate callus on parietal wall; umbilicus well open, with well-marked funicular ridge and circum-umbilical limb which forms a prominent angle where it meets anterior margin.

Type in collection of Mr. R. A. Sutherland, Wanganui.

Height, 32 mm.; diameter, 32 mm.

Localities.—Chatton Creek, Gore;? Trig. M, Totara, small specimen (= P. amphialus of Suter, 1921, p. 88).

Natica (Magnatica) approximata (Suter). (Plate 56, fig. 3.)

1917. Turbo (Marmorostoma) approximatus Suter, N.Z. Geol. Surv. Pal. Bull. 5, p. 6, pl. 2, fig. 5.

The type of Turbo approximatus is in an extremely poor state of preservation, squeezed out of shape, and with the front half of the shell missing. It should never have been described. Fortunately, in the same collection is a fairly well-preserved shell, squeezed in the same manner and undoubtedly of the same species. This was identified by Suter as Polinices huttoni (1921, p. 68). Close relationship exists with P. planispirus Suter (now N. suteri), but there is always a groove running from the umbilicus across the callus towards aperture and slightly upwards. There is a low funicular ridge in the umbilicus, which is moderately open, and bounded by an obsolete arm not definitely marked off.

Localities.—486, Wharekuri greensand; Kakanui tuffs (H. J. Finlay).

Natica (Magnatica) suteri nom. mut. (Plate 56, figs. 2, 5, 6.

1917. Polinices planispirus Suter, N.Z. Geol. Surv. Pal. Bull. 5, p. 10, pl. 3, figs. 1, 2 (not N. planispira of Phillips).

Suter generally identified this species as Polinices huttoni, especially the specimens from the Waitaki Valley. It will be shown below that P. huttoni = P. gibbosus, and is not an openly umbilicated shell like this one. In the original description no mention is made of the low funicular ridge in the umbilicus, but Suter's fig. 1 shows it. The specimens from locality 476, at least, are of variable shape; some have an almost flat summit like the type, others have a fairly high spire (see Plate 56, fig. 5). The size of the umbilical opening and the strength of the funicular and circum-umbilical ridges also are inconstant, so that more specific divisions may be required. At Trig. Z, Otekaike, where these shells are common, occur many large calcareous Naticid opercula which must belong to them, for there is no other shell to which they can be attributed. According to our present system

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of classification, the species cannot, therefore, be placed under Polinices (= Uber), which has a horny operculum. The change to Natica necessitates an alteration of the specific name, for there is a prior Natica planispira Phillips (Illust. Geol. Yorkshire, pt. 2, 1836, p. 224, pl. 14, fig. 30).

Localities.—Blue Cliffs, South Canterbury, immediately above limestone (type); 476, “Kekenodon beds,” Wharekuri; 526, Okoko; 477, “Otekaike limestone,” Station Peak, Waitaki Valley; 733, Orbitolite limestone, Hokianga South Head; Trig. Z, Otiake beds above Otekaike limestone (G. H. Uttley); 1160, Awamoa Creek (J. Marwick).

Natica (Magnatica), nuda n. sp. (Plate 56, fig. 9.)

Shell small, strong; spire low with almost straight outlines, one-quarter of height of aperture; whorls 4, convex, flattened or even concave below tangential suture, which is descending on body-whorl; surface with fine growth-lines only; aperture semilunar; outer lip straight, strongly retracted above to suture, inclined 32° from vertical; inner lip calloused on parietal wall, and thickened again below where basal limb abuts; umbilicus wide, bounded by an obsolete rounded ridge.

Holotype in collection of New Zealand Geological Survey.

Length, 13 mm.; diameter, 13 mm.

Localities.—1134, coast quarter-mile north of Papatiki Stream, North Taranaki; 1117, coast 3 chains north of Maungapuketea Steam, Mimi Survey District, North Taranaki (L. I. Grange).

2. Genus Sulconacca n. gen.

Shell moderate to small in size, smooth, umbilicated; spire low, gradate; protoconch with minute nucleus; suture deeply channelled; aperture semilunar; outer lip straight or slightly concave, sometimes gently retacted to suture, inclined 20° from vertical; inner margin straight, with thin enamel on parietal wall; umbilicus always open, bounded by low ridge outside which is a broad sulcus caused by an angular thickening of anterior apertural margin, on exterior of which is a notch.

Type: Sulconacca vaughani Marwick.

Suter classed all the shells embraced by this genus as Ampullina (Megatylotus) suturalis (Hutton). Megatylotus is founded on a huge shell, N. crassatina Lamk., which has a wide basal callosity covering the umbilicus, and with a folded outer margin; there is an umbilical chink in the young but there is no basal sulcus.

The sulcus also distinguishes Sulconacca from Ampullina, in which the basal limb has the nature of a collar or a step. The ridge bounding the inside of the sulcus of Sulconacca is not unlike that in the Eocene Amauropsina Chelot, which Cossmann (1919, p. 392) considers a subgenus of Natica. In Chelot's subgenus, too, the suture is canaliculate.

Further support for the closer relationship to Natica than to Ampullina is presented by the groups of shells here classed under the new subgenera Carinacca and Magnatica. The small N. haasti, with its impressed suture and no funicle, could easily be mistaken for a Sulconacca, but a careful examination shows that it has the same basal limb as A. waihaoensis, which has a weak funicle, and is related through N. sutherlandi to N. approximata and N. suteri, a shelly-operculate species.

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