284 
GASTEROPODA OF THE INFERIOR OOLITE. 
both genera — a very unusual proceeding. It clearly belongs to the Matliilda-YikQ 
Turritellge. It is possible that two species, or at any rate two varieties, are 
included under T. quadrivittata ; one a wide, the other a narrow form. The 
wider form, which is Phillips’ type, is represented in pi. vii, figs. 11, 12 of the 
above quoted volume of the ‘ Geological Magazine.’ The narrower form is repre- 
sented in pi. vii, fig. 13, and also in PI. 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 : If, 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. Each 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-gvovip have been already indicated. Turritella tricincta, Miinst. 
(Goldf. pi. cxcvi, fig. 11), a fossil of the Lias, may possibly be merely a variety, 
T. eucycla and T. Glapensis may be regarded as elongated and eucycloid varie- 
ties of the quadrivittata-grovop, the former especially coming near to the narrow 
section of T. 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-hedi at Bradford Abbas, develops an additional 
spiral posteriorly ; it belongs to the slender section, and is closely related to T. i 
eucycla, Heb. and Desk 
172. Tueritella. (? Mathilda) cf. binaria, Hebert and Deslong champs, 1860. ; 
Plate XVII, fig. 7. ^ 
I860. Tveeitella bixaeia, Heh. and Desl. Toss. Mont.-Bellay, p. 47, pi. vi, ' 
fig. 7 ; pi. viii, fig. 10. | 
A fragment consisting of four whorls from the Lower Division of the Inferior j 
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- i 
ing the discovery in our Inferior Oolite of more complete specimens. j 
Our fragment shows a spiral angle of about 14°. The whorls, which are 
