INTRODUCTION. 
THE principal object of the present Catalogue has been to give 
a complete list of the Terrestrial Operculated Mollusca, with 
descriptions of all the genera and species known to exist ; indi- 
cating at the same time those contained in the British Museum 
Collection. 
This Catalogue has been prepared by Dr. L. Pruirrer, of Cassel, 
so well known for his attention to the Terrestrial Mollusca. 
JOHN EDWARD GRAY. 
16th September, 1852. 
Y 
