148. 
South Australian Shells. 
S.A. NAT., VOL. XIV. 
Alt.vst 31st, 19 3 3 . 
or submedian equators (section of maximum diameter), or with 
equators more anteriorly placed; after which the oval or round 
section, the small or large apical orifice, and the obliquity of 
the aperture, follow. Subgenus Caduhts, in the restricted sense, 
includes species which are somewhat cask-shaped, short, obese, 
conspicuously swollen in the middle, tapering rapidly toward both 
ends; convex on all sides, though less so dorsally; peristome 
simple, thin; anal orifice large, with simple edge contracted by a 
wide circular callus or ledge just within the opening. This sub- 
genus does not app-ear to be represented in Flindersian waters, 
Cadiia Cray 1847 (subgenus). Decidedly curved, more or les:s 
swollen near the middle or towards the aperture; more tapering 
toward the apex; apical orifice not contracted by a callous ring, 
or with, such callous rine, weak and far within; edges not slit. 
Type — Cadii!ii:> gadns Montague, of uncertain habitat. Species 
located here are usually small and slender. We include: C. ac- 
'inninatiis 4’ate. C. angustior \ erco, C. laezns Brazier, C. occidinis 
\ erco, C. spretiis Tate S: May. 
Polyschides Pllsbr\' S; Sharp 1898. (subgenus). Inflated an- 
terior to the middle or not much bulging: apex cut into a number 
of lobes, 2 :enerally four, by as many slits. Type — Cadulus telra- 
schistus Watson 1879, from Fernando Noronha. Our spiecics 
C. gihhosiis \'erco, belongs here. W e would remark that the 
chief characters of this subgenus are tlic deep slits and prominent 
apical lobes. Typical quadridentate forms appear numerously 
in the Eocene. 
C. acuminatus Tate 1887. “The Acurninated Cadulus.’^' 
Rather tliin. moderately arcuate, not much swollen, fusiform,, 
the greatest girth about the middle, thence very gradually taper- 
ing towards the ends, which are rather large; median bulging 
being about as obvious in a dorsal or ventral as in a lateral view 
of the shell; tube somewhat flattened antero-posteriorly through- 
out. the compression slightly greater at tlie ends; smooth, glossy, 
translucent wliitish, with an opaque white ring a short distance 
frtmi the smaller end, produced by a narrow internal callous 
ledge; both openings oval, their outlines more flattened on the 
convex than on the other side, and both cut the tube nearly at 
rieiit angles; peristome simple. Length 6. diameter at middle 1„ 
aperture .75 mm. Diameter of apex about two-thirds that of 
the aperture. Culf St. \'incent, not uncommon in shell sand, 
(Tvpc locality — Oyster beds of the Upper Aldinga series). ^ Ihe 
specific name is singularly Inappropriate. Specimens vary in ob- 
esity. 44ie white girdle near the smaller end is constantly con- 
spicuous on the milky translucent colour of the rest of the shell. 
