200 GASTEROPODA OF THE INFERIOR OOLITE. 
smooth, and the increase by steps less pronounced. The point where this change 
comes on varies in individual shells. 
Body-whorl angular, smooth, and slightly projecting; aperture oblong, with 
rather a wide and moderately reflexed canal. Section triplicate; one acute fold 
near the centre of the outer wall, one rather wide shallow fold low down in the 
columella, one acute small fold in the posterior wall. 
Relations and Distribution.—This species is essentially the common triplicate 
Nerina of the Oolite Marl horizon, and probably passes by gradations into Nerinza 
attenuata on one side, and Nerinxa expansa on the other. Figs. 4 a and 4b may 
be regarded as typical; figs. 6 and 7 seem to connect it with Nerinza expansa of 
the Lincolnshire Limestone. 
The chief localities are Swift’s Hill and Longridge in the Cotteswolds, and 
similar forms may be traced in parts of the Lincolnshire Limestone. It is some- 
what singular that so abundant a species should have escaped the notice of Lycett ; 
but most species, even the commonest, are wont to be local in distribution. 
131. Nerinza Lonerorpensis, sp. nov. Plate XIII, fig. 5. 
Description : 
Spiral angle (obtuse) . : : elon 
Height of whorl to width F : Ripper ese 
Length : : . 90 mm. 
Shell cylindro-conical, turrited. Whorls about sixteen. The apical whorls, 
as in N. oolitica, are thickened at the suture, though scarcely to the same extent. 
The whorls are much excavated, and this is continued throughout, the more 
mature whorls being much pinched in about two-thirds down, which gives this 
part of the spire a peculiarly constricted look. 
The aperture is oblong, and the section is remarkable for the smallness of 
the folds. 
Relations and Distribution —The pinching in of the outer portion of the 
whorls gives this genus a superficial resemblance to N. cingenda, Phil. Rare in 
the Upper Pisolite of Longfords. 
