278 HELICID^. 



showing the position and shape of the clausilium or 

 ossicle in several species. 



The Clausilia would seem to be more at home in the 

 South of Europe and Asia Minor than in any other part 

 of the world^ judging from the statistics given by Char- 

 pentier in his Monograph on the genus, which was in- 

 serted in the ' Journal de Conchyliologie' for 1852. He 

 enumerated 235 species ; and this number has since been 

 added to by M. Schmidt, who has lately published an 

 exhaustive essay on the same subject. None of them 

 have been discovered in North America. Three species 

 are dextral and inhabit Transylvania. Some of our na- 

 tive Clausilice occur in the upper tertiary strata of Essex, 

 Suffolk, and Norfolk ; and their origin, as inhabitants of 

 Northern Europe, must therefore be very remote. 



A. Shell ribbed or striate transversely : clausilium having its 



margin entire. 



1. Clausilta rugo'sa*, Draparnaud. 



C. rugosa, Drap. Tabl. Moll. p. 63. C. nigricans, F. & H. iv. p. 121, 

 pi. cxxix. f. 1, 2. 



Body dark-grey or slatecolour, with a tinge of reddish- 

 brown, paler at the sides and underneath, indistinctly tuber- 

 cled in such a way as to appear wrinkled: tentacles thick, 

 minutely speckled with black ; upper pair rather close together, 

 with bluntly rounded bulbs which are darker than the ten- 

 tacles ; lower pair decidedly conical, and darker than the upper 

 ones: foot of a rather clear greyish colour, narrowing gra- 

 dually towards the tail, which is tumid and pointed. 



Shell shaped like a long club, but somewhat attenuated at 

 the broader end, not thin and scarcely semitransparent, rather 

 glossy, light-brown or horncolour, with a few transverse 

 streaks and lines of white, marked with numerous and close- 

 set but somewhat irregular stricc in the line of growth, which 

 are curved on the upper and flexuous on the lower wliorls, as 



* Wrinkled. 



