INTRODUCTION. It 
and shake it violently. Obstinate fragments may sometimes be 
removed by a strong thin jet of water made by placing the thumb 
against the mouth of a tap of running water. The C/ausz/@ are very 
hard to clean. I have sometimes, though rarely, succeeded by letting 
them crawl on a plate and pouring boiling water quickly over them, 
when they die with their bodies partly outside the shell and so capable 
of being taken hold of. 
When the animals have been removed, the shells should be 
placed in a basin of clean warm water in which they should all 
be washed with soap and then well rinsed before being put out to 
dry on a piece of blotting-paper. In the case of the minute Pee, 
Vertigos, etc., no internal cleaning is necessary; they may be left 
to dry up and then washed. Most shells are improved by a gentle 
application of soap and hot water with a moderately soft tooth-brush ; 
and some that are often encrusted with hardened mud, as the Vzuz- 
pare, should be carefully scraped with a pen-knife. I have sometimes 
found common washing-soda more effective than soap for the fresh- 
water species. But it is a fatal mistake to use aczd in any form. 
The operculum of those species which possess one should be 
gummed on to a plug of cotton-wool inserted in the mouth of the shell. 
Bivalves. 
A pen-knife carefully inserted will separate the animal from the 
shells of the bivalves, which should be instantly tied up or screwed up 
in a piece of tissue paper till dry. Should this not be done, the liga- 
ment will harden with the valves open, and the shell cannot then be 
closed without snapping the ligament. 
Slugs. 
A set of slugs preserved in spirit forms an interesting feature in 2 
collection ; and some guidance is necessary here. 
