512 Transactions. 
4. Genus Ѕіхом Bolten, 1798. 
a. Subgenus SINUM s. str. (= Sigaretus Lamarck, 1799). 
* Shell depressed, auriform, spirally striated or furrowed. Spire very 
low with rapidly widening whorls. Aperture greatly distended ; operculum 
horny."—(Zittel.) 
Type: Helix haliotoidea Linné. 
Sinum fornicatum Suter. (Plate 60, figs. 4, 9.) 
1917. Sinum fornicatum Suter, N.Z. Geol. Surv. Pal. Bull. 5, p. 11, pl. 3, fig. 5. 
alities.—Maerewhenua River, right bank (Uttley, 1920, p. 150); 
480, “Island sandstone," Waihao River; ? 176, Black Point, Waitaki 
Valle 
This shell is more elevated than the typical Sinum with its extremely 
flattened body-whorl and айу inclined convex outer lip. The umbilicus 
also is fairly open, only one side being covered by the reflexed inner lip; 
but it is nearer to Sinum s. str. than to Eunaticina. The Black P 
specimen is more inflated than the others, and may be a separate 8 
Occurrences of this genus are very rare in New ЖА the three ix 
= oe represented each, as far as the writer knows, by only one 
specim: The uniformly low horizon is note worthy: in all cases these 
ак occur in the basal marine sandstones just above the coal-measures. 
Sinum infirmum n. sp. (Plate 60, figs. 7, 8.) 
Shell very small, fragile, depressed auriform, of about three and a half 
whorls, of which the smooth protoconch occupies over two and 
ire surface of body-whorl with fine slightly шын spiral 
grooves crossed by convex growth-lines; aperture oval, oblique, gean y 
dilated ; outer lip strongly convex; inner lip broken away; umbilicus 
open but small. 
Holotype in collection of Mr. H. J. ee 
Height, 2mm.; diameter, 3-5 oe 
Locos —Ardgowan (type) ; $ 
The type is a juvenile; a ment. from Ardgowan is from à shell 
that was about 10 mm. in diameter when complete. 
S. infirmum can be distinguished from S. fornicatum not only by йя 
smaller size, but also by its much flatter spire. 
b. Subgenus Eunarictna Fischer, 1885. 
Shell longitudinally oval, spirally striated, umbilicated ; body-whotl E 
diste E. 
flattened ; aperture nded; outer lip convex, moderately inclined ; 
columella with a bulge opposite the umbilicus 
Type: N. papilla Gmelin. 
rem Ss cinctum (Hutton). (Plate 60, figs. 12, 16.) 
. Sigaretus ( 
„РІ. 18, fig. oe 
18 acleay Mem. 
» pi. 
1918. Sinum. ал (Hutton) ; Suter, Alph. List N.Z. Tert. Moll., p. 25. 
Although this s in many lists of New Zealand 
pecific name appears 
Mollusea, none of the Specimens examined by the writer was correct 
"bed 
: 
(Naticina) cinctus Hutton, Trans. N.Z. Inst., vol. 17, P 318. P - 
Vol., p. 55. 7 
1915. Polinices (Buopira o а (Hutten): Suter, N.Z. Geol. Surv. Pal. Bull. 83 — 
NS oh гарла 
