localities referring to the general distribution of the species, 
or which have been filled up from other sources. 
The authenticity of some of the localities printed in italics, 
is very doubtful, but in such cases I have merely given the 
locality attached to the specimen, leaving the point to be 
cleared up by future enquiry. 
A considerable number of the shells in the collection were 
named when I undertook their arrangement, but as I have 
gone over and verified the name of most of the shells. I 
alone am responsible for any errors.in the determination of 
species which may hereafter be detected. 
Many species are not determined to my own satisfaction, 
but such must ever be the case where no means exist for 
comparing obscure or doubtful shells with other collections, 
and a mere figure and meagre description, (and Reeve’s 
descriptions are too often such) are all one’s available 
resources. 
Many of the shells in the collection are in very poor order, 
and others have been more or less injured by want of care, 
and the use of wax in mounting them (a plan ill suited for 
any shells, specially delicate ones), and the accumulation of 
dust in the cases, which in some places was } of an inch 
thick. The Rotelle have been entirely stripped of their 
beautiful polish by the action of some microscopic confervoid 
growth, which a varnish would probably obviate, and this 
circumstance, (the liability of highly polished shells to be 
deprived of their lustre even in close cases,) should be borne 
in mind, and a remedy applied in future. 
