﻿350 



EOCENE MOLLUSCA. 



Nebita teicaktnata, Morris. Catal. Brit. Foss., 2nd edit., p. 264, 1854. 

 — — J. Lowry. Chart Brit. Tert. Foss., pi. iii, 1866. 



Spec. Char. N. Testa ovatd, supra convexd, subtus convexiusculd ; anfractibus tribus, 

 ultimo magno, spiraliter tricarinato ; spird relusd ; aperturd semicirculari ; area columellari 

 plana, margine minute denticulate-, labro acuto. 



Diameter, i- 6 -ths of an inch. 



Localities. Bracklesham {Edwards). 



France : Retheuil, Cuise-la-Motte, Houdan {Deshayes). 



The figure I have given is from a specimen in Mr. Edwards' cabinet. The shell lias 

 a fine denticulation on the sharp edge of the columella, but appears to be destitute of any 

 prominent tooth on that edge, so far as I have been able to detect, in which respect it 

 seems to agree with Deshayes' figure. The inside of the outer lip, however, appears to 

 be free from those denticulations which usually ornament those species which are grouped 

 under the generic name Nerita. This species is especially distinguished by being 

 ornamented with three prominent spiral ridges, between which the surface is covered with 

 regular and somewhat fine stria?. This species is said by M. Deshayes to be common in 

 some localities of the Paris Basin, especially in the sands of Cuisse-la-Motte. He also 

 observes that several varieties of it occur in the Calcaire grossier. I am not aware of its 

 having occurred in England in any other bed than the Bracklesham. M. Deshayes thus 

 describes the operculum of this species (' An. sans Vert, du Bas. de Par./ t. iii, p. 17) : — 

 " II est lisse en dessus, obliquement partage par une etroite depression, qui part du 

 sommet. II est fort remarkable en ce qu'il porte deux apophyses ; l'une subapiciale, 

 bijide, e'est celle qui existe invariablement dans toutes les especes ; Pautre mediane 

 consiste en une proeminence aplatie et pointue, qui glisse en dessous du bord 

 columellaire.' , 



