KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 52. N:o |G. 97 
3. Subfossil mollusea from the caves at Chillagoe. 
Planispira praehadra n. sp. (Pl. 3, figs. 101—103). Shell depressed, conical, 
with slightly raised spire and inflately convex basal portion, separated by a sharp 
peripheral carina. Whorls slightly convex, nearly flattened and separated by shallow 
sutures, the last one shortly descending in front. Aperture oblique, broadly lunate, 
with the lip slightly expanded; columella perpendicular with reflected margin, half 
covering the small umbilicus. Sculpture: whole surface roughly rugated in oblique 
direction, here and there two systems of rugae crossing each other; the rugae car- 
rying lengthened hair scars placed in spiral series. Colour milky white, somewhat 
translucent, with two light brown bands, one above and the second just below the 
peripheral carina. Maximum dimensions: diameter 25; height 16.5; h. of aperture 
11, br. of ap. (from columellar to outer lip margins) 14 mm. Whorls 5 ?/4. 
About eight large and small shells were collected, most of them covered with 
an earth crust, under which the surface of the shell had a fresh appearance. The 
species is closely related to the large forms of Planispira from Queensland, described 
by HEDLEY in 1912, but it differs from them in its more elevated spire and in its 
rough sculpture with the elongated hair scars, which strongly recall the sculpture of 
Hadra forsteriana. The new species appears to be a transition form between the 
Jatter species and a large Planispira, such as P. delicata HEDLEY (1912). In its 
young state H. forsteriana is still more like P. praehadra in its keeled periphery, 
but the shape of aperture, with its sloping, not horizontal, under-margin, distin- 
guishes it from the present species. 
Microcystis antiqua n. sp. (Pl. 3, figs. 104—106). Shell depressed, conical, 
with slightly projecting spire and well rounded body wbhorl, narrowly umbilicated; 
suture broadly margined. Aperture produced lunate, with simple peristome, the outer 
lip immediately declining from body wbhorl, evenly rounded all round, under lip 
somewhat convexlv projecting in the middle, columellar margin not reflected but 
somewhat thickened and with a small sinus. Surface with microscopical spiral 
striae and slight rugations across the whorls, the latter appearing most obviously on 
the base. Within the umbilicus a few furrows appear at the columellar margin. 
Max. dimensions: diameter 7.5, height 4.5; h. of aperture 3.1; br. of ap. 3.7 mm; 
whorls 5 !/s. 
Though very like M. fulva, the above species differs from it in possessing a 
somewhat more elevated shape and a more contracted spire, so that 5 complete 
whorls are present at about 6 mm diameter; further the umbilicus is a little wider 
and furnished with some distinct furrows within. It resembles M. fulva in having 
the under lip of aperture broadly convexly projecting, wherein it differs from M. 
rustica; on the contrary, it resembles the latter in its elevated form and the distinct 
K. Sv. Vet. Akad. Handl. Band 52. N:o 16. 13 
