G3 
fitting sutures ; umbilical cavity large extending the entire 
length of the spire 5 aperture unknown ; ornament not 
preserved, probably a nearly smooth shell. Length (average) 
two and a half inches. 
Obs. — In the internal cast the whorls are more convex, and 
the sutures well defined. (PI. viii., Fig. 5.) 
Under the name of Niso ? darwinii , the late Prof, de Koninck 
described* a small shell from the Upper Silurian, probably 
Wenlock, beds of Yass, possessing the peculiar continuous 
umbelical tube of the recent and Tertiary genus Niso . We 
now have from Lilydale a similar although much larger shell, 
possessing the same character. I have made a longitudinal 
section of a Niso from the Muddy Creek beds in Victoria 
(PI. ix., Fig. 1), and a comparison with that of our more 
ancient fossil, will at once indicate their close resemblance. 
In the vertical section of both the umbilical tube is visible, 
and this can also be seen in one of Prof, de Koninck’s 
figures f of the Yass species. There is a like correspondence 
between the cross sections of the two shells (PI. viii., 
Figs. 3 & 4), bearing in mind that the section of the recent 
species is near the apex, and that of the fossil near the base. 
Niso is known in time as far back as the Middle or Lower 
Tertiaries, and its connection with the Palaeozoic forms is 
continued through the Secondary rocks by the genus Palceoniso, 
Gemmellaro. 
The material before me is not sufficient to enable me to work 
this sjDecies out in its entirety, but I find myself in the same 
difficulty as did Prof, de Koninck, in definitely referring so old 
a form to a recent and comparatively young genus, geologically 
speaking. I suspect that the ultimate examination of more 
perfect specimens will reveal an organization differing from 
Niso , in which case I would propose for it the name Vetotuba.\ 
Family Turbinidje. 
Genus Cyclonema, Hall , 1852. 
(Pal. *N. York, ii., p. 89.) 
Cyclonema ? australis, sp. nov. 
(PI. ix., Figs. 4 & 5.) 
Sp. Char . — Shell turbinate, modcratey elongated, much 
expanded below, — whorls six, ventricose, the body whorl 
disproportionately larger than the others, — aperture more or 
less circular ; umbilicus not visible ; operculum unknown 5 
whorls traversed by successive spiral keels, which are always 
# Rech. Foss. Pal. Nouv. (Julies <lu Slid, 1876, Pis. 1 & 2, p. 127, t. 4, f. 11. 
f Loc, tit,) f. 11c. 
X Vetus, old ; tubus, a tube or pipe. 
