CERITHIUM. 173 
Sowerbyi-bed at Bradford Abbas, and the variety C occurs on what is nearly the 
same horizon at Beaminster. It has occurred to me that possibly Cerithiwm 
Lorieri, D’Orb. (Prod., i, 271), from the Bajocian of the Sarthe might in some 
sense represent this species. 
102. CrRiTHIUM POLYSTROPHUM, sp. nov. Plate X, figs. 12, 13. 
Description : 
Length (estimated) : ‘ . 55mm. 
Width : 5 ; . 105 mm. 
Spiral angle : : vy ar, 
This species so nearly approaches Cerithiwm abbas, var. B, that it is best 
described by comparison with that form. The shell is more uniformly subulate, 
having a narrower spiral angle; the whorls are all convex, the principal convexity 
being rather below the middle; there is no trace of a shoulder in any of them. 
The spiral striz are very close, regular, and equal. In the earlier whorls (fig. 13) 
the ornaments consist of about half-a-dozen such striz, those adjoining the sutures 
being slightly crenulate; in the mature whorls these lines increase in numbers till 
they are not far short of twenty. 
The body-whorl is rather short in comparison with the entire shell; aperture 
ovate-elongate, with a well-developed anterior canal. 
Relations and Distribution.—This fossil is rare in the Lincolnshire Limestone 
of Weldon. The condition of the few specimens is by no means satisfactory, so 
that its actual relations to C. abbas cannot be fully made out. 
103. CERITHIUM OBORNENSE, sp. nov. Plate X, fig. 11. 
Description : 
Length (restored) - F . 60mm. 
Width . ; : =) 122mm, 
Spiral angle : : : seco 
Shell elongate, somewhat turrited ; spiral angle regular. Whorls numerous, 
flat, and sub-concave, much broader than high, and slightly rising towards the 
sutures, which are bounded on either side by a raised rim, of which that on the 
lower side is the strongest. The ornaments consist of numerous fine spiral 
lines of somewhat unequal thickness, and they diminish somewhat in strength 
anteriorly. 
