142 EOCENE MOLLUSCA. 
angustd ; labro sub-marginato, ints crenulato, posticé dilatato ; columella recta, quinquies 
plicaté. 
Shell oblong, ovate, with a very short obtuse spire, formed of but few whorls, the 
sutures of which are barely separated from each other; the body-whorl, which of 
itself forms almost the entire shell, is widely but not deeply notched in front. The mouth 
is long, narrow, and curved at the posterior extremity ; the columella straight and, 
generally, furnished with five folds, occasionally with six or even more; the an- 
terior folds are larger and more oblique than the others, which decrease in size as 
they ascend the columella. The outer lip is curved, expanding near the suture into a 
rounded wing-shaped projection ; it is finely crenulated within, slightly thickened, and 
presents a narrow raised border running along the outer margin. 
Some confusion appears to exist between the present species and a living species 
common in the Mediterranean (JZ. miliacea), placed by Lamarck in his genus Volvaria. 
This latter species is mentioned by Dujardin as occurring in the miocene formation in 
the neighbourhood of Tours ; and Philippi and Sismonda have also recorded it as found 
in the upper miocene of Piedmont. Dujardin’s shell, however, appears to be distinct, 
and the identification of the last is very questionable. The same species is also 
cited by Grateloup, although with a query, as identical with the present species, to 
which he has referred some shells from the miocene beds of Bourdeaux and Dax; but 
which, as well as certain shells from the synchronous beds of Turin, described by 
Michelotti as 1/7. ovwlata, belong to a different species to which D’Orbigny has given the 
name JV. sub-ovulata. On the other hand, aMarginella from the miocene beds near Vienna, 
formerly considered to belong to the present species, has been regarded by Hérnes as 
identical with .Z. miliacea, and Philippi has also recorded a shell from Westeregeln, as 
belonging to the recent species. Dr. Beyrich, however, has pointed out with 
much precision, the specific differences between the J. miliacea and M. ovulata, and 
he seems to think that the shells mentioned by Hornes and by Philippi, belong in fact, 
to the present species, which, apparently, is confined to the older tertiary formations ; 
while, as yet, there isno ground for considering that J/. mcliacea occurs in any formation 
older than the upper miocene, if it occur even in that. 
Whether or not the German shells are referable to the present species, is a doubt- 
ful question. The figure given by Dr. Beyrich does not agree with the French shells ; 
the spire is more produced ; the aperture, consequently, is proportionally shorter, and 
it is wider in front; the outer lip, apparently, is without the wing-shaped projection so 
characteristic of the true J/. ovulata ; and the folds on the columella are more distant 
and more oblique. Bronn’s shell, so far as an opinion can be formed from the some- 
what coarse and indistinct figure given by him, appears to agree much better. 
The specimen figured is, I believe, unique, and although not in a very good state 
of preservation, is sufficiently so for determining the identity. 
Size.—The French specimens of this species vary considerably in size, some ex- 
