MOLLUSC A OR UNIVALVES. 173 



They are found principally in Europe, but a 

 few species are from America: they derive 

 their name from the resemblance of the shell 

 in shape to the pupa or chrysalis of an insect. 

 One species is named the Pupa chrysalis, — 

 Several species are found in England under 

 stones, old walls, and in woods. 



43. Clausilea. — Shell fusiform or 

 spindle-shaped, rather resembling the 

 last genus, but more slender; aper- 

 ture irregular, rounded or ovate ; lips 

 united; summit obtuse. Animal like 

 the Helix. — There are nearly 150 spe- 

 cies recent, and 1 fossil.* 



The Clausilece inhabit mosses at the 

 foot of trees. Some species are English, and 

 many are found in other parts of Europe, parti- 

 cularly on the borders of the Mediterranean ; and 

 Russia and the Crimea produce a great number 

 of curious species, which have lately been dis- 

 covered ; so that it is thought there are more 

 than 150 species: a few also are American. 



* There are 44 species described by Lamarck and 

 | Deshayes, but many more species have been discovered 

 lately. 



