PREPARATION OF MARINE ANIMALS.
349
muscular bands are well seen. In another slide the animals
have been cut open longitudinally, stained with carmine, and
spread open. In these the above-named structures are well
seen, and also the oviducts filled with ova.
I cannot show better illustrations of the advantage of proper
staining than different species of Medusidae. They should be
at once put into formalin diluted with about nine times its
volume of water, and deposited for some time in a fresh solution,
in order to remove all the sea-salts. Without staining most
species would be far too transparent and colourless. Good
results may be obtained with Aurelia aurita by staining with
carmine, and on the whole I think it is better to add a little
sulphurous acid to the solution. The general character is then
shown to great perfection; and in some specimens the anatomi-
cal structure of the testes, ovaries, and eyes is well seen. I have
also obtained excellent results by staining with port wine in
diluted alcohol. In some cases it is impossible to arrange
Aurelia so as to show a side view in proper perspective, but I
have succeeded by keeping the animal in diluted alcohol with
picric acid, which, when of proper strength, causes the specimen
to be sufficiently plastic to take the desired form.
Small Cyanea make excellent slides mounted on their sides
and stained with methalin blue, so as to be of nearly the natural
colour of some individuals. All my good specimens of Rhizostoma
have been collected in the Crouch near Burnham. Their
general characters are excellently seen when stained with
carmine, the net-work structure and the eyes being well shown.
The detailed structure of Cydippe is well brought out by keeping
the animals in diluted formalin, and staining with carmine. By
careful management most excellent results may be obtained.
I now proceed to cases in which it is necessary to decalcify
the animals with dilute acids. As an example, I select
Scrobicularia piperata stained with carmine. This shows to
great perfection the form of the shell and almost the entire
anatomical structure of the animal. For many years I never
attempted to prepare slides of Pagurus (the Hermit Crabs), but
more excellent results may be obtained by keeping the animals
in diluted sulphurous acid to dissolve out the carbonate of lime
and reduce the colour. The general form and structure of the
legs and claws is well shown, and the muscles which work them
are perfectly visible, being stained by the pigment which was