160 GASTEROPODA OF THE INFERIOR OOLITE. 



81. Cerithium Beanij, var. Weldonis, sp. nov. Plate IX, figs. 6 a, 6 b, 6 c; 6' a, 



6' b, 6' c, 6' d. 



Description. — Sub-variety A with five spirals. Three specimens are figured 

 figs. 6 a, 6 b, 6 c), each showing some difference of ornament or condition. The 

 usual form is decidedly pupoid, and the ornaments are rather coarser and 

 more open than in the Dogger specimens. It often happens that in the sub- 

 apical whorls the tubercles are so fused together axially as to produce a costate 

 appearance. The uppermost row of spirals is very strongly tuberculated, and the 

 distinctions as to the fineness of the third and fifth spirals not so strong as in 

 Dogger specimens. Specimens of G. Beanii from the Inferior Oolite of Cleeve 

 much resemble these forms, though slightly larger. These are in Mr. Brodie's 

 collection. 



Sub-variety B with four spirals (figs. 6' a, 6' b, 6' c, 6' d). The ornamentation 

 is, on the whole, similar to the preceding, but the general form of the shell is 

 more stumpy. This, for the sake of distinction, we might term C. Beanii- 

 quadricinctum. 



There are also other forms with four spirals approaching G. limseforme. 



Relations and Distribution. — The fossils described under the above heading, as 

 G. Weldonis, afford an excellent example of the proneness to change of form and 

 ornament in these small pupoid Gerithla. They are very abundant in the 

 Lincolnshire Limestone of Weldon, and less so at other fossil-localities in that 

 Limestone, where for the most part their place is taken by C. limseforme 

 and its relatives. 



82. Cerithium quadricinctom, Miinster, 1844. Not figured. 



1842 — 1844. Cerithitjm quadricinctum, Miinst. G-oldfuss, Petr. Germ., t. 173, 



fig. 11. 



The sub-varieties of G. Beanii with four spirals are passing into the form 

 figured by Goldfuss, but their ornaments are less regular and the shell more 

 pupoid. Very rarely, however, specimens occur in the Lincolnshire Limestone, 

 where the granulations are small and regular, and the shell less pupoid. These 

 we seem justified in referring to G. quadricinctum. 



