163 
The reproductive system, a partial dissection of which is 
here shown, demonstrates that the species is included in 
XaiitJionitlon , as opposed to I'l/ersifes. 
Shell depressedly globose, narrowly perforate, substance 
rather light and thin. Colour cinnamon-brown, paler on the 
base. Whorls five, parted by shari^ly impressed sutures. 
Periphery rounded, but the flattening of the whorl above 
suggests an incipient keel. The last whorl descends at the 
aperture deeply and abruptly with a wavering suture. Sculp 
ture : the first two whorls are smooth to the eye, but under 
the lens fine vermiculate etchings appear. The adult sculp- 
ture commences suddenly, and consists of close, fine, irregu- 
lar, backwardly curved riblets, which grow lamellate near the 
aperture. During their traverse of the whorls the riblets 
sometimes unite, divide or end untimely, while fresh threads 
may be intercalated. At the periphery the riblets are especi- 
ally prone to anastomose, on crossing the base they become 
finer and more regular. Umbilicus very narrow, deep, with 
a furrow entering spirally from under the columellar expan- 
sion. Aperture oblique ovate, outer lip broadly expanded, 
margins united by a callous ridge, columella partly arching 
over the umbilicus. 
Maj. diam., 22 mm. : n)inor diam., 18 mm. : height, 
15 mm. 
Hah. — Musgrave Ransfes. 
Xanthomelon wilpenense, Tate. 
Hadra it /Jprnr/isis^ Tate, Trans. Rov. Soc, S.A., 1894, 
p. 193. 
Hah. — Musgrave Ranges. 
Xanthomelon radiatum, n. sp. 
Plate XXX., figs. 4, 5, 6. 
Shell lenticular, solid, narrowly perforate, spire slightly 
elevated. Last whorl bluntly angled at the periphery, rather 
swollen, and then much contracted behind the aperture. 
Colour uniform isabelline. Whorls four, parted by an im- 
pressed suture. Sculpture : First tw^o whorls microscopi- 
i2 
