342 GASTEROPODA OF THE INFERIOR OOLITE. 
which it may be distinguished by its uniformly smaller habit, by its more 
transverse shape, and by the fact that the longitudinal (7. e. radial) varices are 
relatively larger and extend across the entire body-whorl. But, as noted by the 
authors, the varices vary much in magnitude, so that in some specimens they are 
nearly obsolete. Under these circumstances the shells are not easily distinguished 
from Neritopsis, ef. decussata, Minster. 
Although regarded by Morris and Lycett as a Great Oolite species, I am 
somewhat doubtful of the occurrence of Neritopsis varicosa in the Great Oolite 
of Minchinhampton. On the other hand, it occurs not unfrequently in the Oolite 
Mar! of the Cotteswolds, and more rarely in the Pea-grit. 
275. Nerivopsis, ef. pecussata, Minster, 1844. Plate XXVIII, figs. 5a, 5b, 5c. 
1844. Narioa pecussara, Miinst. Goldfuss, Petref. Germ., pl. excix, fig. 10. 
As a species from the Coral Rag. 
1852. NeEriropsis pEcussata, Miinst. D’Orbigny, Terr. Jur., vol. ii, p. 227, 
pl. ecci, figs. S—10. 
The species described above (N. varicosa) gradually shades off into cancellated 
forms such as those figured in the accompanying plate. I might also refer to 
Neritopsis cancellata, Moore (‘ Quart. Journ. Geol. Soc.,’ vol. xxii, p. 548, pl. xv, 
fig. 20), and to some of the forms described under N. Guerrei, Héb. and Desl. (‘ Bull. 
Soc. Linn. Norm.,’ vol. v, p. 185, pl. i, fig. 4). Cancellated forms of this kind seem 
to occur on more than one horizon. There are two specimens from the ‘‘ Base- 
bed ” at Lincoln, one of which is figured in the accompanying plate. The aperture 
is somewhat more angular on the columellar side than usual. 
276. NeERITOPSIS INCISA, sp. nov. Plate XXVIII, fig. 2. 
Description : 
Height . : ‘ : . 125 mm. 
Width ‘ - ' : . 16 mm. 
Shell transversely ovate-oblong; spire extremely few-whorled and very low. 
Body-whorl relatively enormous, with a somewhat flattened posterior area. The 
ornaments consist of about ten or twelve extremely rugose radial ribs, irregularly 
developed and divided by deeply-cut sulci. These are decussated throughout by 
