348 EOCENE MOLLUSCA. 
less of the original colour remaining upon them; but those I have from Milford, which 
appear to be of the same species, though rather larger, are destitute of colour or markings 
of any kind. The upper part of the outer lip is generally, though not always, slightly 
elevated above the vertex, and somewhat thickened within, at some distance from the 
edge. The inner lip is thick and flattened, with a sharp edge to the columella, which 
has a few denticles in the centre and a distinct tooth at the upper part. 
This species seems to partake of the characters by which the genus JVerifa is 
distinguished as well as of those of the genus Weritina, in which I have placed it. 
No. 271. Neritina Forsesu, S. Wood. Tab. XXXIV, fig. 16 a—e. 
Spec. Char. N. Testdé ovato-oblongd, levigatd, tenuissime lineolatd vel ornatd ; 
spird depressé; anfractibus rapidé crescentibus, aperturd semilunari expansd ; area 
columellari lata, pland, in medio tenuissimé denticulatd ; labro acuto simplict. 
Diameter, 2ths of an inch. 
Locality. Weadon Hill (S. Wood). 
This is equally abundant with JV. aperfa, and I have separated it in consequence of 
its difference in form. Our present shell is narrower; that is to say, it has a more 
extended outer lip, the aperture being wider or more expanded from the inner lip to the 
outer than in the preceding species. The apex is also much depressed, and the upper 
part of the shell is nearly flat, with spire indicated by a narrow depressed suture. The 
coloured markings are various. 
I have obtained several specimens of this species with its operculum in position, and 
this adjunct I have had figured. The inner side of the operculum is furnished with a 
prominent projection at the lower part, which is bifid or forked, expanding at an angle of 
about 45°. The outer side of this operculum shows a curvilinear depression with a 
corresponding elevation on the inner surface. V. Fordesdi much resembles JV. fluviatilis, 
but that shell has a more elevated spire. It does not differ greatly from JV. ¢ransversa, 
Ziegler, figured by Rossinasler, ‘ Icon.,’ pl. vii, fig. 121, but I have not specimens of 
that species with which to compare it. 
No. 272. Neritina zonuta, 8. Wood. Tab. XXXIV, fig. 19. 
Spec. Char. WN. Testé rotundato-ovatd, levigatd ; vertice depresso ; anfractibus con- 
veniusculis, zonulatis aut parum angulatis, superné concavis; lineolis fuscis parallelis 
