556 Transactions. 
of — 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 lime- 
stone (type); 476, “ Kekenodon beds," Wharekuri; 526, Okoko; 477, 
* Otekaike limestone," Station Ae Waitaki Valley ; 133, Orbitolite 
limestone, Hokianga South Head; Trig. Z, Otiake beds above Otekaike 
limestone (G. H. Uttley) ; 1160, rois 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, idi 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 18, coast quarter-mile north of Papatiki Stream, North 
Taranaki; 1117, coast 3 chains north of Maungapuketea Steam, Mimi 
Survey District, North Taranii- (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 
nen retacted to iban inclined 20? from vertical; inner margin straight, 
thin enamel on parietal wall ; niil always open, bounded by 
box ridge outside which is a broad sulcus caused by an angular thickening 
of anterior apertural margin, on exterior of which is a notch. 
Туре: Sulconacca vaughani Marwick. 
Suter classed all the shells embraced by this genus as Ampullina 
ален suturalis (Hutton).  Megatylotus is founded on a huge shell, 
assatina Lamk., which has a wide basal callosity covering the um- 
Жы: and with a folded outer махра there is an umbilical chink in - 
the young but there is no basal suleus 
The sulcus also distinguishes ганц from Ampullina, іп which the 
basal limb has the nature of a collar or a step. on ridge bounding 
the inside of the sulcus of Sulconacea is not unlike that in the Eocene : 
Amauropsina Chelot, which Cossmann 1919, bgenus 
of Natica. In Chelot’s subgenus, too, д : 90 moni a subg 
Further rudes for the eloser relationship to Natica than to Ampullina 
is presented re the groups of shells here classed under the new subgenera 
Carinacca and 
ае" could easily ` 
examination shows that it has the same basal limb as А. waihaoensis, 
N. approzimata and N. suteri, a shelly-operculate species. 
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