58 MOLLUSCA FROM THE GREAT OOLITE. 
NERITA HEMISPHHRICA, Roemer, Plate X1, fig. 16, 16a; 14, 14a. 
NERITA HEMISPH#RICA, Roemer. 1836. Nordd. Oolith.,‘p. 156, t. 10, fig. 7. 
NV. Testé levigatd, transversd ovali-hemisphericd; spird parvd, prominuld; apertura 
semilunart; labio interno magno, convexo et incrassato. 
Shell smooth, transverse, ovately hemispherical ; spire small ; aperture semilunar ; inner 
lip large, convex, and incrassated. 
The surface of this species varies considerably ; the younger specimens being smooth, 
and not unfrequently exhibiting portions of colouring in dark, encircling lines: the older 
specimens are rendered rugose by numerous large plications of growth. It is not 
uncommon, being found in all the shelly beds, more especially in the coarse planking. 
Locality. Minchinhampton Common. 
Nerita minvuta, Sow. Plate XI, figs. 19, 19a. 
NerivTa MINuTA, Sow. 1824. Min. Con. t. 463, figs. 3, 4. 
— — Desh., 1838. Lam. Anim. sans Vert., 2d Edit., vol. viii, p. 617. 
— — D’Orb. 1850. Prod. Paléont., p. 299. 
—  PULLA, Roemer. 1836. Nordd. Oolith., p. 155, t. 9, fig. 30. 
— ovata, Roemer. Nordd. Oolith., p. 156, t. 10, fig. 6. 
— mats, Buvignier. 1843. Mém. Soc. Phil. Verd., t. 5, figs. 18, 19. 
N. Testa parva levigaté; spird obliqué exsertd et minutd; anfractu ultimo coloribus 
Tineatis undulatis sepissime picto. 
Shell small, smooth; spire oblique and minute; the last whorl most commonly exhibits 
undulating-coloured lines, which occasionally coalesce, and are very irregular. 
This little shell is a longer oval figure than both Wertta hemispherica (Rom.) and 
Neritina Cooksoni (Desl.); the latter little species, with which it nearly agrees in size, is 
more globose, and has a larger, more prominent, and less oblique spire than JV. Pula. 
NV. minuta occurs abundantly in all the shelly beds; its surface is very smooth and shining; 
the most frequent size is that of duck shot ; the longer diameter not exceeding two lines. 
Locality. Minchinhampton Common and neighbouring district. 
Scr. 3. Inner lip notched. Neritopsis, Grateloup. 1840. 
N. Testé crassa, neritiformi, ovato-globosd; spird parva, obliquad, anfractu ultimo 
inflato, costis numerosis cincto ; apertura suborbiculari, labro externo incrassato et levigato, 
labio interno concavo, sulco lato margine excavato. 
Shell thick, neritiform, ovately-globose; spire small, oblique; the last whorl inflated, 
encircled with numerous coste; aperture suborbicular; the outer lip thickened, but smooth; 
the inner lip concave, with a wide notch upon its inner border. 
