80 EOCENE MOLLUSCA. 



aperture. On the columellar lip are three similar teeth, one, very large, close to the 

 columella. 



I have not been so fortunate as to meet with any specimen having more than 

 fragments of the shell preserved ; the description therefore is principally taken from 

 casts. The chief characters presented by them, namely, the large pliciform teeth 

 and the produced aperture, are, however, plainly shown. The specimen represented 

 by figs. 6 a and 6 b is, I apprehend, the young shell. 



Size. — My most perfect specimen of the mature shell has apparently lost the upper 

 six or seven whorls ; in its present state it presents six whorls only. The length of 

 the axis is 6-10ths of an inch, nearly; the diameter 2-10ths, nearly. In a perfect 

 state it was probably nearly an inch long. 



Locality. — Sconce, where it is very rare. 



Genus 11th. Succinea.* Braparnaud. 1801. . 



Amphibulima, Lamarck, 1805; Hartm., 1821. 

 Amphibulimus, Mont/., 1810. 

 Cochlohydba, Fe~rus., 1819. 



Gen. Char. — Shell ovate, or ovately conical, rather elongate ; volutions few ; spire 

 short, pointed ; aperture large, entire, longitudinally ovate, oblique ; peristome sharp, 

 not thickened nor reflected, and confluent with the columella ; inner lip spread over a 

 part of the body whorl ; columella smooth, sharp-edged, with an imperforated axis. 



This genus, first created by Draparnaud, has been received without question by all 

 Malacologists except Ferussac, with whom it forms the sub-genus Cocldohydra in his 

 extensive genus Helix. The animals, like all others of this family, present a strong 

 general resemblance to the typical Helix ; but, according to M. Deshayes, they offer 

 modifications of the generative organs, which differ alike from those of Helix and of 

 Bidimus. Lamarck, in ignorance of Draparnaud's genus, proposed his genus Am- 

 phibulima, which he afterwards suppressed, adopting the name given by Draparnaud. 

 The shells are distinguished from Bidimus by the thin outer lip, and the rapidly 

 enlarging whorls ; and from Limncsa, to which they more nearly approach in general 

 form, by the columella, which is thin, smooth, and sharp, and destitute of the oblique 

 fold which characterises the columella of the latter genus. 



The Succinea are strictly land animals ; for, although frequently covered by water 

 and capable of long submersion, they live habitually on land in damp marshy places, 

 near the margins of pools or ditches. 



The living species are not numerous, and are found chiefly in temperate climates. 



* Etym., Succineus, of amber, i. e., amber-coloured. 



