282 HELICID^. 



folds is less prominent but often cruciate : outer lip thick and 

 rather broad, white or cream-coloured and inflected : basal 

 crest short and curved : umbilicus indistinct : clausilium 

 oblong, regularly curved, slightly contracted above. L. 

 0-5. B. 0-15. 



HABITAT : Under stones, in the bark of trees, and 

 among dead leaves, in Kent, Sussex, and Hants, as well 

 as in Gloucestershire, but hitherto found only in a few 

 places. This species is one of our upper tertiary fossils. 

 It is not uncommon in the North and South of France, 

 Belgium, and parts of Germany. Probably it is also a 

 member of the Scandinavian fauna, assuming Nilsson's 

 variety /3 of C. plicatula to belong to the present species. 

 His diagnosis, although too short and indefinite for 

 satisfactory identification, appears to agree with the 

 main characters of our shell. 



This species differs from C. plicatula (for which it 

 has been mistaken) in being more than twice the size, 

 much more ventricose and of a paler colour, in the spire 

 being more abrupt, and especially in the striae being 

 closer and more numerous in proportion to the size of 

 the shell. From C. rugosa and its variety dubia this 

 differs in being also more ventricose and of a lighter 

 colour, as well as in having much coarser striae and in 

 being destitute of the distinct spiral striae, which impart 

 to the last-mentioned shell a decussated or slightly gra- 

 nular appearance. The mouth of the shell in C. Rolphii 

 is, besides, larger and broader. The shell in this as well 

 as the other species varies considerably in respect of the 

 length of its spire and the development of its teeth and 

 basal crest. C. Mortilleti of Dumont is, according to 

 Schmidt, only a synonym of the present species ; although 

 Mr. Benson at one time considered that they were 

 distinct, and pointed out the difference between them in 

 the ' Annals of Natural History ' for July 1856. 



