KUNGL. SY. VET. AKADEMIENS HANDLINGAR. BAND 52. wz:o [6. 99 
be searched for in the districts named and not among the recent Helicinidae of the 
Australian continent, belonging to Aphanoconia, subg. Sphaeroconia, or to Palaeohe- 
licina, subg. Ceratopoma (cf. WaGN»ER 1911). 
Omphalotropis minuta n. sp. (Pl. 3, figs. 113, 114). Shell turreted, with con- 
vex, tumid whorls, coarsely spirally lirated and with irregular faint lines of growth, 
the apex (l—]*/: whorls) smooth, bulbiform; base somewhat smooth, with fainter 
spiral lines; aperture somewhat oblique, ovate, peristome simple, rather thick, colu- 
mellar margin oblique, straight or a little convex, callous, so as to nearly cover the 
umbilicus; lips connected by a rather thick parietal callus. Umbilicus narrowly con- 
tracted, furrow-shaped, bordered by a nearly obsolete umbilical keel. Colour light 
grayish, aperture with a feeble tint of orange within. Max. dimensions: height 2.5; 
br. l.s; h. of aperture 1; br. of ap. 1 mm; whorls 4 '/e. 
This species, of which 8 specimens of various sizes were collected, seems to 
belong to the group Stenolropis, on account of its nearly obsolete umbilical keel (ef. 
Kogsett 1906). In its lirate sculpture it resembles O. conella SyxKrs (1902, Proce. 
Mal. Soc. London) from New Hebrides, but it differs from this and other species of 
the genus in lacking a peripheral carina on the last whorl, in having a less number 
of whorls, and in its small size. No operculum was found. The occurrence of this 
form of a chiefly Polynesian group in the caves of Chillagoe is very interesting, as 
no member of the genus lives nowadays on the continent of Australia. This locality 
(Australia) given by PreirreR for his O. malleata is doubtful (cf. Kopetr 1906). 
Microphyura microdiscus (Bavay) (PI. 3, figs. 115—118). Shell depressed, 
orbicular and almost discoidal, with slightly convex spire and a broadly excavated 
umbilicus, occupying a third of the shell diameter. Whorls narrow, the last one 
shouldered, slightly bent down in front. Aperture somewhat contracted, narrowly 
lunate with continuous peristome, thickened all round; outer lip reflected, inner lip 
projecting as a transversal plate from body whorl. Parietal wall with 2 teeth, the 
upper one longer, terminating before reaching the inner lip; outer wall smooth 
inwardly. Surface microscopically sculptured with close spiral lines, most distinct on 
the peripheral part of the base, and obsolete lines of growth; umbilicus smooth 
within. Colour yellowish white. Max. dimensions: diameter 1.7; height 0.6; h. of 
aperture 0.4 mm. Whorls 3 ‘/s. 
About ten shells were collected, all of them being of a subfossil appearance 
and covered with earth. They agree completely with the figures and descriptions 
given by Bavay (1908, p. 283, pl. XIV, fig. 10). Bavay, who does not, however, 
mention the microscopic sculpture, has referred the species to Polygyra, but in con- 
sideration of the geographical distribution of this genus, which is exclusively North 
American, I include this species in the genus Microphyura Anony, since it has a 
striking resemblance, on the one hand, to M. (Diplomphalus) microphis Crosse 
from New Caledonia, on the other, to M. hemiclausa Tate (1896), from Central 
Australia. From both, however, it differs in possessing teeth on the parietal wall 
