14 INTRODUCTION. 
or circular of various sizes. The rectangular boxes should be 
chosen so as to fit the drawers of the cabinet as nearly as possible, 
and should all be equal in height. Unfortunately they are expensive. 
A cheaper method is that of a series of glass tubes from 4 to I inch 
in diameter. These are very handy and allow of the contents being 
turned over to see the under side of a specimen, which is impossible 
with boxes. The mouths of the tubes should be plugged with cotton 
wool, which is a better dust excluder than cork, though perhaps not 
so neat. Glass tubes may now be bought very cheap, and of all 
shapes and sizes; but those who do not care to go to the expense of 
buying them can easily make them in the following manner. Buy a 
few yards of glass tubing (which is exceedingly cheap) of the desired 
thickness, nick the surface with a file and with a comparatively slight 
pressure the tubing will snap in two at the nick with a straight edge. 
Tubes so made will, of course, have two open ends. 
Some arrange their shells on cotton wool in cardboard trays. This 
method has the advantage of allowing the specimens to be easily 
changed and if necessary taken up and handled. These trays may be 
obtained from many naturalists. 
Minute shells may be kept in the small glass tubes already men- 
tioned. <A series of the commoner species can be mounted on a strip of 
card, which is put into a tube or glass-topped box. Some of the delicate 
white species, as Helix pulchella, Cectliordes acicula, etc., are better 
shown on black. Where a very delicate object has been in question I 
have stuck a wire into the lower surface of a cork and fixed the object 
to the other end of the wire, so that when the cork is put into the 
tube the object does not rattle and is held in position in the middle of 
the tube. 
For mounting shells on card Gum Tragacanth should always be used 
as it does not glaze when dry like Gum Arabic. 
A valuable shell should never be stuck down, but placed in a nest 
of cotton wool in a glass box or tube. 
