CENSUS OF THE OLDER TERTIARY FAUNA OF AUSTRALIA. 397 
the outer lip is slightly sinuous towards the suture, and interiorly 
is furnished with small denticles. 
My opinion regarding the generic location of certain fossil species 
herein referred to is the result of a comparison with many speci- 
mens of Columbella alba, Petterd, a recent species in Southern 
Australia, which has a very close resemblance to Mitromorpha 
lirata, A. Adams—the type of the genus. 
Firstly, there is a distinct, though small, sutural sinus, which 
demands the relegation of the genus to Pleurotomidx. Secondly, 
the columella-ridges are inconstant in number, and though two 
are usually present, one or both are not infrequently absent. 
The development of columella-ridges, and denticles on the inner 
aspect of the lip, belongs to the senile stage of growth, so that 
immature specimens will not exhibit these characters; but whether 
or not, the plications and denticles are always produced at the 
adult stage, I have no means of judging as there are no external 
developments which might indicate that that stage had been 
attained. One diagnostically known species, among others, of the 
Australian Eocene is here referred to the genus. it is :— 
Mitromorpha daphnelloides, Ten.-Woods (sp.). 
1879 Mitra daphnelloides, Tenison-Woods;' 1893 Raphitoma 
daphnelloides, Tate,® list name. 
This species has for an analogue Buchozia cancellata, Dantz, 
and Dollfuss, of the Miocene of Touraine, but differs, apart 
from more conoid shape and details of ornamentation, in having 
usually two oblique ridges on the columella, though some 
specimens of M. daphnelloides apparently adult, have the ridges 
obsolete. However in one of the two specimens of the Touranian 
Species, which I possess, two plaits are discernible, clearly, there- 
fore the two species are congeneric. These determinations prolong 
the range of the genus into Miocene for France, and Eocene for 
Australia. 
* 
aetna 
1 Proc. Linn. Soc., N. S. Wales, Vol. tv., p» 7, t. 2, fig. 3. 
2 Trans. Roy. Soc., 8. Aust., Vol. xvi, p. 221. 
