162 GASTEROPODA OF THE INFERIOR OOLITE. 



84. Certthium (species or variety). Plate IX, fig. 8. 



A single specimen from the shelly freestones of the Cotteswolds presents the 

 zonal arrangement of G. Pontonis in a more complex form ; the zone in the upper 

 part of each whorl being made up of three granulated spirals instead of two. As 

 a means of distinction merely I would propose to call this Cerithium " cingula." 



85. Cerithium Wansforditr, sp. nov. Plate IX, figs. 9 a, 9 b, 9 c. 



Description : 



Length . . . .6 mm. 



Width .... 2-75 mm. 



Spiral angle .... 30° — 35° 



Shell short, subcorneal, turrited; apex obtuse, but angle of increase nearly 

 regular in the majority of specimens. Number of whorls about nine, flat, very 

 narrow, and richly ornamented. Suture well marked. The subapical whorls are 

 ornamented with from two to three spirals, whose tuberculations are fused axially. 

 In the anterior whorls the richly cut spirals are three in number, the two upper 

 ones being strongly tuberculate and generally fused axially. 



The body- whorl is rather more than one-third the entire length of the shell, 

 and similarly ornamented ; the spiral lines on the base are finer than those on the 

 flank. The aperture is subquadrate and contracted with a relatively large 

 anterior canal, which is reflexed. 



Relations and Distribution. — Although evidently related to G. limseforme, this 

 species is, in the majority of cases, conical rather than pupoid, with a rather wide 

 base for a Cerithium. Nevertheless, there are many connecting links. Indeed, 

 the whole of the small Cerithia of the Lincolnshire Limestone are so linked by 

 connecting forms that, under some aspects of the case, they might be regarded as 

 one and the same species, represented by local varieties. G. Wansfordise is the 

 prevailing form about Wansford and Barnack, though met with occasionally, but 

 in a modified form, at the other localities. 



86. Cerithium Georgit, sp. nov. Plate IX, fig. 10. 



Description : 



Length . . . . .12 mm. 



Width . . . . .3 mm. 



Spiral angle .... Very convex. 



