76 EOCENE MOLLUSCA. 
edges, and costellation of the volutions, in the shape of the aperture, and in the 
character of the columella; and I consider it, therefore, as merely a variety. It is a 
ventricose shell, with a shorter spire, and more convex whorls; the aperture is longer 
in proportion, exceeding the spire in length, owing probably to the shell not having 
attained maturity. The specimen, the only one I have seen, belongs to Mr. D’Urban’s 
collection. 
Size.—Axis 1 inch and 6-10ths; diameter, | inch, nearly. 
Localities.—Sconce, Shalcombe, Binstead, Isle of Wight. 
Genus 9th. Pupa.* Lamarck. 1801. 
CocuLoponta, (sp.), Férussac. 
CocHLopina, (sp.), Férussac. 
CocHLoGENA, (sp.), Férussac. 
Gen. Char.—Shell cylindrical, elongated, or sub-globose ; apex generally obtuse, 
sometimes acuminated ; whorls numerous, slowly increasing, the last smaller than the 
penultimate one; frequently striated or ribbed; aperture generally elliptical, some- 
times sub-quadrate in front, and rounded behind; peritreme continuous, slightly 
incrassated and reflected; outer lip dentated; teeth variable in number; one or two 
plaits on the columella. 
The present genus is one of the dismemberments effected by Lamarck of Bruguiére’s 
genus Helix. The organisation of the animal bears a strong general resemblance to 
that of the animals of Helix and Bulimus; and Ferussac has reunited the genus to 
Helix, in which it is distributed among the sub-genera Cochlodonta, Cochlodina, and 
Cochlogena. The shell, however, prevents striking dissimilarities, and in the animal, 
according to M. Deshayes, the same modifications of the generative organs occur 
which distinguish the animal of Bu/imus. The elongated cylindrical form of the spire, 
the proportion of the last whorl to the penultimate one, and the direction of the 
aperture which is parallel with the axis, distinguish the shell from /He/ixv ; and it is 
separated from Lwlimus by the numerous and slowly increasing volutions, and by the 
teeth and folds with which the outer lip and the columella are furnished. It is to 
Clausilia that it bears the closest resemblance ; but from that genus it is separated as 
well by the aperture as by the absence of the clausium, a character which, however, 
can seldom be available to the Paleeontologist. 
In the animals of several of the smaller species the peduncles only exist, the ten- 
tacles becoming obsolete. Some of these species are sinistral and hyaline, and form 
Miiller’s genus Vertigo. The animal, however, exactly resembles Pupa in everything 
but the absence of the tentacles, and, inasmuch as their disappearance is very gradual 
* Etym., from a supposed resemblance to the Pupa or Chrysalis of some insects. 
