234. GASTEROPODA OF THE INFERIOR OOLITE. 
both genera—a very unusual proceeding. It clearly belongs to the Mathilda-like 
Turritelle. It is possible that two species, or at any rate two varieties, are 
included under 7. quadrivittata; one a wide, the other a narrow form. The 
wider form, which is Phillips’ type, is represented in pl. vu, figs. 11, 12 of the 
above quoted volume of the ‘ Geological Magazine.’ The narrower form is repre- 
sented in pl. vu, fig. 13, and also in Pl. XVII, fig. 6, of the present work. 
Description—Accepting, at least provisionally, the view that both wide and 
narrow forms belong to one species, the spiral angle will range from 18°—28°. 
The height of whorl to width is about as 1 : 13, and the average length may be 
about 20 mm. 
The spire consists of from ten to twelve whorls; apex unknown. The whorls 
are sub-globose, sutural sulcus wide with sometimes a faintly-marked rim in the 
centre. Hach whorl is ornamented by four granular spirals, the third being the 
strongest and most granulated. The cross-hatching is close and sinuous, decus- 
sating with the spirals so as to form nodes. Base nearly flat, and spirally 
striated: aperture suborbicular. 
Relations and Distribution.—The differences which separate this species from 
the opalina-group have been already indicated. Twrritella tricincta, Miimst. 
(Goldf. pl. exevi, fig. 11), a fossil of the Lias, may possibly be merely a variety, 
T. eucycla and T'. Clapensis may be regarded as elongated and eucycloid varie- 
ties of the quadrivittata-group, the former especially coming near to the narrow 
section of 7’. quadrivittata. 
Rare in the Dogger and Millipore-bed; a single specimen from the Lincoln- 
shire Limestone of Weldon. A variety, which occurs in the shell-bed at Pit- 
combe, and also in the concavus-bed at Bradford Abbas, develops an additional 
spiral posteriorly ; it belongs to the slender section, and is closely related to T. 
eucycla, Héb. and Desl. 
172. Turriretta (? Mathilda) cf. sinarta, Hébert and Deslongchamps, 1860. 
Plate XVII, fig. 7. 
1860. TurrireLta Binarta, Héb. and Desi. Foss. Mont.-Bellay, p. 47, pl. vi, 
fig. 7; pl. viii, fig. 10. 
A fragment consisting of four whorls from the Lower Division of the Inferior 
Oolite near Beaminster presents so many points of resemblance to the Callovian 
species from Montreuil-Bellay that I feel justified in making this reference, pend- 
ing the discovery in our Inferior Oolite of more complete specimens. 
Our fragment shows a spiral angle of about 14°. The whorls, which are 
