196 
HORN EXPEDITION—MOLLUSCA. 
Thersites sublevata, Tate. (Plate XVII., Fig. 5.) 
Hadni sublevata, Trans. Hoy. Soc. S. Aust., vol. xviii., p. 192, 1891. 
Shell clepressedly orbicular, slightly convex above, flatly rounded at the side, 
convex below. Wliorls live, of slow increase, moderately convex, narrow, sepa¬ 
rated by an impressed suture. Last whorl obtusely angled at the periphery, 
thence convex to the suture; the side flatly rounded, becoming nearly perpen¬ 
dicular in the anterior one-fourth, thence widening to the post-labial constriction; 
the base regularly and broadly convex. Aperture oval, its posterior angle 
considerably in advance of its outer basal margin; peristome white-lipped, its 
margins approximate and connected by a thin callus, thinly reflected, more thickly 
on the columella; basal lip bordered by a shallow constriction commencing at the 
umbilical margin and continued to about the middle of the side, producing a 
conspicuous elevated ridge within the aperture; anterior part of body-whorl 
slightly descending; columella obliquely arched. Umbilicus wide, about one- 
sixth width of base, slightly narrowed by the columella-reflection. 
Colour. —Yellowish-brown above, opaque-white beneath. 
Sculpture densely granulate all over ; growth-folds in deep sigmoid curves 
from the suture to the umbilicus, with interstitial growth-stria3 on the side and base 
of last whorl. 
Dimensions. —Diameters, 15 and 14 ; height, 8 ; height of last whorl, 6 ; 
width of umbilicus, 2*5. 
Affinities. —In the presence of the constriction at the base of the aperture 
and the elevated ridge within the aperture the present species assimilates to 
H. ivesselensis, Cox, from which it differs by depressed shape, less deformation in 
the anterior part of the body-whorl, short arched columella, absence of a colour- 
band, and more particularly by its granulated test {H. zvesselensis is absolutely 
devoid of this style of sculpture). 
The specific name is in allusion to the up-raising of the base of the aperture 
to form the inteimal ridge. 
Localky. —Hart Ranges. 
Thepsites adcockiana, Bednall, sp. (Plate XIX., Fig. 26.) 
Hadra adcockiana, Bednall, Trans. Roy. Soc. S. Aust., vol. xviii., p. 190, 
wdcts., 1894. 
