NERIN AA. 215 
151. Nerinma (Piygmatis) prsouitiva, Witchell, 1887. Plate XV, figs. 3 a—c, and 
Plate XVI, fig. 7. 
1887. Neninxa Pisonitica, Witchell. Vol. cit., p. 82, pl. i, fig. 6. 
Description : 
Spiral angle : : : . d—d*. 
Height of whorl to width . ; a) Devie25; 
Approximate length ‘ : . 80—200 mm. 
Shell cylindrical, subulate. Whorls numerous, of moderate length, flat, 
sutural prominence scarcely marked. Assuming that fig. 3 b represents the apical 
conditions, there are numerous fine spiral lines in the earlier whorls, whilst the 
later ones appear to have been perfectly smooth. 
In section the outer wall has two folds, the anterior of which is very large and 
complex; the posterior fold is small and flat-headed. On the columellar side the 
anterior fold is expanded and angulated, the middle fold is almost simple, the 
posterior fold is deep and bifurcated. 
Relations and Distribution.—The internal structure easily distinguishes this 
species from any member of the Oppelensis-group, where the section exhibits seven 
folds ; the whorls also are perfectly flat throughout, whilst in most of the members 
of the Oppelensis-group they are excavated, at least in the earlier stages. 
It is described by Mr. Witchell as abundant in the pisolitic beds near Stroud, 
and at Longfords near Nailsworth. It occurs also in the Pea-grit at Crickley. 
There is a variety with rather shorter whorls, a rather wider spiral angle, and 
with the apical whorls slightly excavated, which occurs in a hard arenaceous rock 
about halfway between Seven Wells and Snow’s Hill. This is said to be on the 
horizon of the Oolite Marl. Very long specimens showing the characteristic 
internal structure of Ptyg. pisolitica occur in the Inferior Oolite of Otley Hill (Mr. 
Walford’s collection.) The fragment from Weldon (PI. XVI, fig. 7) also oreatly 
resembles this species, which, if this identification be correct, appears to possess a 
wide vertical range. The shell-bed at Weldon is undoubtedly high" in the Inferior 
Oolite series, but there is probably a mixture due to remané forms. 
1 When I spoke of the Lincolnshire Limestone as being in the Lower Division of the Inferior 
Oolite an exception should have been made as regards the fossiliferous beds of Weldon and Great 
Ponton (see antea, p. 73). 
