166 GASTEROPODA OF THE INFERIOR OOLITE. 
91. Crritaium turRis, Hudleston, 1884. Plate IX, fig. 15. 
1884, Crrtruium rurRis, Hud. Geol. Mag., dee. iii, vol. i, p. 61, pl. iii, fig. 13. 
Description : 
Length ; ; 5 :; . 13 mm. 
Width : : 3 . 475 mm. 
Spiral angle (mean) . ; Segoe 
Shell rather short, strongly turrited ; spiral angle somewhat convex Whorls 
about twelve in number, flat and short, suture close. The ornaments are con- 
spicuous. Seven spirals are counted on the penultimate, consisting of wavy lines 
drawn out spirally, at considerable intervals, producing a sort of basket-like pattern. 
The longitudinals are strong, and close together, especially in the upper part of 
each whorl, but are on the whole irregular. 
Aperture subquadrate to oval, with a well-developed anterior canal. 
Relations and Distribution.—This is more widely angled and less pupoid than 
average specimens of O. Beanii, has a more complex system of ornamentation, and 
is more strongly turrited. Very rare in the Yorkshire Dogger. 
92. Crrivutum (species). Plate X, fig. 1. 
Description.—Probable length 28 mm., width about one-fourth ; spiral angle 
about 18°, and tolerably regular. The shell is scarcely turrited. The upper balf 
of the specimen is not sufficiently preserved for description. Whorls subtumid 
with very close sutures, the sutural angle being but little inclined. The ornaments 
consist of numerous fine spiral lines which are decussated at wide intervals by 
irregular nodular coste, with a tendency to curve and incline from left to right. 
These costz are usually the most developed anteriorly, and this causes the 
preceding whorl to project somewhat over the succeeding one—a feature the 
reverse of turriting. The number of the nodular longitudinals is about seven. 
Aperture ovate with indications of an anterior canal. 
The specimen under consideration comes from the Inferior Oolite of Rodborough 
Hill, and was regarded by Lycett as a Cerithium. It has some resemblance to C. 
varieulosum, Desl. (vol. cit., p. 210, pl. xi, fig. 46), a fossil of the Upper Lias of 
Fontaine-Etoupefour. 
