HORN EXPEDITION—MOLLUSCA. 
195 
not sculptured. T. bordaensis is depressed iind somewhat carinated, which, through 
T. tonisetti, connects with T. evandaleana to Badistes. The corrugations of 
T. bordaensis have disappeared in T. tonisetti, though the shape remains. The modi- 
lication of form in another direction is to T. silveri, which is globosely conic, but 
with a subangulated periphery ; T. clydonigera has a rounded periphery, and by 
its regular sculpture connects with Angasella. In all these species the peristome 
is incomplete, but in T. howardi it is continuous, and extensively projects 
forward ; the last whorl is moreover strongly deflected at the front. T. arcigerens 
oH’ers the same features, though not so lenticular in shape. By the form of the 
aperture they approach Angasella. 
Thepsites (Glyptophagada) clydonigepa, Tate. (Plate XTX., Fig. 24). 
Reference— -Hadra clydonigera* Tate, Trans. Roy. Soc. S. Aust., vol. xviii., 
p. 193, 1894. 
Shell globosely conical, spire elevated; test thin. Whorls five, of somewhat 
rapid increase, moderately convex, separated by a linear suture. Last whorl 
moderately and abruptly descending at the front, moderately inflated, rounded at 
the periphery, base convex. Aperture oblique, suboval •, peristome narrowly 
expanded and slightly reflected, margins connected by a thin callus; columella 
oblique, straight, thinly reflected, half-concealing the umbilicus. Umbilicus small, 
about one-eighth the width of the base. 
Colour unknown, but apparently without bands. 
The sculpture consists of flexed regular acute costie, narrower than the inter¬ 
spaces, which, on the body-whorl, form deep sigmoid curves, extending from suture 
to within the umbilicus. The embryonic one-and-a-half turns are devoid of costa3 
but are minutely granulated. The intercostal spaces are obscurely, transversely, 
and distantly striated. 
Dimensions .—Diameters, 16 and 14; height, IDS. 
Locality. —McDonnell Range, received from Rev. H. Kempe (one bleached 
example). 
Affinity.—^\\\% species resembles H. silveri, Angas, from whieli it difters by 
its convex periphery and more numerous and less interrupted costie, 65 on the 
body-whorl of the former and 50 on that of the latter. 
« Bearing, Idiidon (the surge), in allusion to wavy surface. 
