GASTEROPODA. 



187 



Small shells, very like Clausilia, but without the clau- 

 sium; they are found in moss at the roots of trees in 

 Britain and Europe. B. fragilis and B. perversa are 

 British species. 



Tornatellina. Beck. (Strobilus Anton ; Elasmatina 

 Petit.) — Shell not umbilieated, egg-shaped or lengthened; 

 the aperture longitudinal, with irregular or thickened 

 edges ) the columella twisted and truncated, and having 

 a fold. Animal unknown. — A few species. 



From the South Sea islands. 



Clausilia. Draparnaud. — Shell fusiform or spindle- 

 shaped, very slender ; aperture irregular, rounded 

 or ovate, almost always sinistral ; lips united ; a 

 bony appendage attached to the inner lip, used as 

 an operculum. Animal, short and usually broad, 

 obtuse behind, with stout clavate upper tentacula, 

 and very small lower ones. — 180 species; also 

 fossil. 



The Clausilice inhabit mosses at the foot of trees. 

 Some species are English, and many are found in 

 other parts of Europe, particularly on the borders 

 of the Mediterranean; Russia and the Crimea produce 

 a great number of curious species, which have lately 

 been discovered : a few also are American. They are all 

 small shells, the largest scarcely exceeding an inch in 

 length. Within the mouth, in the last whorl but one ? 

 there is a little elastic shelly plate attached to the shell, 

 and called a clausium, from which the genus takes its 

 name. It is used to close up the aperture when the 

 animal has retreated within its shell, and in that respect 

 resembles an operculum, or epiphragma; but differs, in- 

 asmuch as the latter are either attached to the animal, 

 or are loose and thrown off, whereas the elausium is 



