COLLECTING AND CLEANING SHELLS.
Shells are described as live and dead shells. Live shells are those
found with the animal enclosed, and are more likely to be perfect in
form and colour than dead shells. Dead shells found amongst rocks are
nearly always battered and worn, and useless from the collector's point
of view. Live shells are found below high water mark, among rocks, or in
the sand, or amongst seaweed and marine grasses.
Wait till a storm from the sea is ended, and then, if the wind is
blowing from the land, a rich harvest of live and dead shells will be
found on the sandy beaches and amongst the seaweed and wrack that comes
ashore. Many of the smaller shells will be found amongst the leaves and
roots of kelp. Start early in the morning, or pigs, rats, and seabirds
will have destroyed the choicest specimens. Even such solid bivalves as
the Dosinia will be carried skywards by the gulls and dropped on to a
hard part of the beach, so that the shells may be cracked and the gulls
get the contents. Most birds have this habit; even thrushes can be seen
carrying snails up in the air and dropping them on to paths. Soak the
dead shells in hot water for a few hours to get rid of the salt, and
then scrub with a hard brush, or, if encrusted or very dirty, rub with
sand, using a brush or cloth. No need to fear hurting them, unless very
fragile, in which case the best thing is a soft toothbrush, with fine
sand. If patches of dirt, or encrustations, still remain, scrape with a
piece of hard wood or a knife. As a last resource use muriatic acid,
diluted with an equal volume of water; but be careful to put it only on
the spots to be cleaned, using a penholder, or small stick, with a small
piece of rag tied to the point. The inside of the shell, if discoloured,
can be cleaned in the same way. When cleaned, wash again carefully, and
dry thoroughly. Then rub the shell with a mixture of sewing machine oil
and chloroform in equal parts. The machine oil, being fish oil, will
replace the oil the shell has lost, and chloroform is the best restorer
of colour we have. For very delicate shells poppy oil is sometimes used;
but it is expensive and difficult to obtain.
The greatest trouble is getting the animal out of live shells. Anthills
are few and small in New Zealand, so the lazy man's method of putting
shells on an anthill, and letting the insects do the work, is
impracticable. Boiling for a minute will not hurt the stronger and
heavier shells; but even pouring boiling water on the more delicate
shells will cause them in time to fade. After taking the shells out of
the boiling water, let them cool, and then place them in cold, fresh
water for a couple of days in summer or for a week in winter, changing
the water every day. The animal can then usually be removed with a
bradawl, or, better still, a sail needle stuck into a cork. Although
soaking in fresh water for a few days makes the animal slip out more
easily, still a large proportion will break during extraction. The piece
left behind must also be extracted, or the shell will be offensive. The
coarser shells can be buried for a few months in sandy soil, or for a
few weeks on a sandy beach below high water mark, or put in baskets or
bags made of twine or netting, and placed in tidal pools, or fastened to
stakes at low water mark, where the marine insects will quickly do their
share of the work. Or they may be buried in a boxful of clean sand or
sandy soil, and the sand kept moist by watering it every few days. The
box is all the better for being put away in a damp place under a tree,
or on the shady side of a building or fence. This, however, is a slow
process, and if the specimens are required at once, the best way is to
extract all you can of the animal by the hot water and soaking process,
and then keep the shell half-full of water in a shady place, every
morning holding it under a water tap and shaking it carefully. After
each shaking a very little pure muriatic acid may be put into the shell,
and when all the effervescing from the acid is over, wash and shake it
again. Two or three mornings of this treatment should clean the shell.
The more delicate shells will lose their colour if put into boiling
water, so first put the boiling water in a basin and then place the
shells in it. Nearly all salt water shellfish, if soaked for a few hours
in fresh water, will die. The only exceptions I know of are the Nerita
and Littorina, families which are semi-amphibious. The best way to
remove coral or vegetable growths from shells is to leave them for a few
weeks, or if very hard, for a few months, in a shady place, where the
wind and rain can get at them, but not the sun. The growths will then be
sufficiently soft to be scraped off with a piece of hard wood or a
knife, or rubbed off with sand. It is a good plan to oil or paste
calico over portions not covered with growths, so as to reduce the risk
of the colour fading. When the animal is removed and the growth cleaned
away, wash, scrub, and dry, as with dead shells.
Shellfish are sometimes obtained by dredging with a naturalist's dredge,
or by diving for them, or lifting them out of the water with instruments
such as hay forks and hooks. Sandy beaches and banks yield many of the
most beautiful specimens, but only with experience will the collector be
able to identify the marks of the syphons of the various shellfish.
Nearly all shellfish that burrow have two syphons, or tubes, which they
push through the sand. The water is drawn down one syphon and up the
other; and as it passes through its stomach the mollusc absorbs the
animal and vegetable particles in the water. Some of these shellfish
live feet below the surface of the sand; some, such as the common
cockle, only a fraction of an inch. Apparently even cockles do not come
to the surface, except to die. Some instinct seems to urge a shellfish,
when sick unto death, to save its fellows from infection by leaving the
common shelter. Cockles found on the surface are to be avoided as
unhealthy, and, unless they die naturally, are soon killed by the
carnivorous shellfish. It does not take one of the whelk family long to
bore a hole in the centre of the cockle shell. It knows too much to risk
having its radula, or tongue, nipped off by putting it between the
partly-open valves of the dying cockle. The end of the syphon, which
projects from the sand, is like a miniature sea anemone. Each
sand-burrowing shellfish has a different shaped end to its syphon, and
the skilled collector can tell at a glance what shellfish is down below.
If he can grip the syphon with his hand he will have no difficulty in
digging up the shellfish, even such a deep-living one as the Panopaea
(Plate VIII., Fig. 3), one of which was captured by Mr. C. Spencer on
Cheltenham Beach, near Takapuna Head, in Auckland Harbour. I believe
this was the only Panopaea captured in New Zealand in situ, and was
about eighteen inches below the surface of the sand at half-tide mark.
If he miss gripping the syphon he will probably lose the shellfish; as
it can burrow nearly as fast as a man can dig with his hand. A beginner
cannot do better than take a small spade, and walk along a sandy beach
at low water. As the tide begins to rise, and the buried shellfish feel
the water, he will see the sand moving, or showing signs of life; and if
he digs quickly enough he may unearth rare and beautiful specimens for
his cabinet.
Wherever animals or vegetables are crowded, disease appears. This is
true of molluscs, and it is seldom worth while looking for a specimen
fit for a collection where any particular kind of shellfish lives in
great numbers. Animal and vegetable parasites will be found wherever
shellfish are crowded together. For instance, a perfect cockle, or one
good enough for a collection, will not be found on a cockle bank, but
solitary ones must be looked for elsewhere.
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