174
LAND AND FRESH WATER MOLLUSCA.
this process is, that unless the solution is of sufficient strength, and
unless the tentacles are extruded when the animal is immersed, it
generally, but not invariably, fails. Some slugs appear to be more
susceptible to the action of the fluid than others; and it generally
answers better with full-grown than with young specimens. But if
successful the specimens are as satisfactory as could be desired; and
even if unsuccessful, they are a great deal better than those preserved
in spirit; for although the tentacles may not be completely extruded,
they are more or less so.' "
The Testacellae, or shell-slugs, may be preserved by partially drying
them in sand and removing the soft parts through a slit in the length
of the foot, filling up with cotton wool, and completing the drying
process.
As to the best mode of exhibiting shells in the cabinet, opinions
differ. They may be gummed on slips of card or on thin slabs
of wood covered with paper; kept loose in card-board trays, or,
better, in glass-topped card-board boxes. We much prefer the last-
named method for many reasons. Being thus protected from dust
they retain their natural appearance better; nearly allied species or
specimens of the same species from different localities may be dis-
tinguished without risk of their getting mixed, and the bottom of
each box serves as a tablet whereon to pencil the collector's notes
of localities or habits. If square or oblong boxes are chosen, the
larger being multiples of the smaller, they can be arranged with
great neatness in the cabinet drawers or covered wood or card-
board trays, and any particular box can be taken out for examina-
tion of the specimens without disturbing the others. Glass-topped
boxes can now be obtained at a moderate price from most of the
naturalists' agents in London, or elsewhere. Great care should be
exercised to keep a record of specimens from varied localities, and
in cases where doubt may hereafter arise, a small number label may
be gummed to the shell, or, better, the number may be painted upon
it in thin oil-colour with a fine brush, such numbers referring, of
course, to a register or diary kept by the collector.
[In any catalogues or papers treating of the Land and Freshwater
Shells which may appear in our journal, we propose to follow the Con-
chological Society's List (2 1/2d each, or 1s. 6d. per dozen, obtainable
from Mr. J. W. Taylor, St. Ann Street, Leeds). This is mainly based
on "British Conchology ; or an account of the Mollusca which now
inhabit the British Isles and the surrounding seas; with particulars of