84 GASTEROPODA. HELICID. 
pillars. I have never seen good specimens from any other 
spot. Height three-eighths of an inch. Colour pale-horn, 
sometimes tinted with dirty-luteous. 
Genus 36. CLausILia. 
Clausilia, Drapernaud, Férussac. 
Testa valdé elongato-conica, ad apicem extremum subma- 
millato-obtusa. Apertura obovalis, ad sinistram posticé abrupteé 
coarctata. Peritrema perfectum, marginatum, reflexum. 
Umbilicus canaliculatus. Operculum internum, posticé pro- 
cessu tenui, spirali, elastico instructum. Tentacula inferiora 
brevissima. 
Synopsis Specierum. 
* Operculo emarginato. 
1. laminata. Testa subventricosa, cornea, leevi, nitida, pellu- 
cida; apertura bilamellata. 
** Operculo integro. 
bo 
Rolphii. Testa subventricosa, subpellucida; anfractibus 
transversim elevato-striatis; apertura bilamellata: inter- 
stitio biplicato. 
3. biplicata. Testa fusiformi-ventricosa, subopaca ; anfractibus 
transversim elevato-striatis ; apertura bilamellata. 
4. rugosa. Testa fusiformi, gracili, subpellucida ; anfractibus 
transversim crebro elevato-striatis ; apertura trilamellata ; 
lamella 1 posticd, 1 dextra, altera parvula antica. 
Shell very elongately-conic, its apex terminated by a some- 
what obtuse nipple. Aperture oblongately-ovate, its hinder 
margin abruptly contracted on the left side. Peritreme per- 
fect, margined, reflected. Umbilicus canaliculated. Opercu- 
lum internal; its hinder part produced into a slender spiral 
and elastic process, terminating more or less gradually in a 
point. The aperture has generally two elevated lamellze, which 
ascend into the last whorl, gradually approximate, but do not 
touch each other. Inferior tentacula very short. 
This genus was first discovered by Drapernaud, who named 
