History of Animals
of these is an intimate one. In colour it looks like a white membrane,
and this is what people extract; and if it be removed and squeezed
it stains your hand with the colour of the bloom. There is a kind of
vein that runs through it, and this quasi-vein would appear to be in
itself the bloom. And the qualities, by the way, of this organ are
astringent. It is after the murex has constructed the honeycomb that
the bloom is at its worst. Small specimens they break in pieces,
shells and all, for it is no easy matter to extract the organ; but
in dealing with the larger ones they first strip off the shell and
then abstract the bloom. For this purpose the neck and mecon are
separated, for the bloom lies in between them, above the so-called
stomach; hence the necessity of separating them in abstracting the
bloom. Fishermen are anxious always to break the animal in pieces
while it is yet alive, for, if it die before the process is completed,
it vomits out the bloom; and for this reason the fishermen keep the
animals in creels, until they have collected a sufficient number and
can attend to them at their leisure. Fishermen in past times used
not to lower creels or attach them to the bait, so that very often the
animal got dropped off in the pulling up; at present, however, they
always attach a basket, so that if the animal fall off it is not lost.
The animal is more inclined to slip off the bait if it be full inside;
if it be empty it is difficult to shake it off. Such are the phenomena
connected with the porphyra or murex.
The same phenomena are manifested by the ceryx or trumpet-shell;
and the seasons are the same in which the phenomena are observable.
Both animals, also, the murex and the ceryx, have their opercula
similarly situated-and, in fact, all the stromboids, and this is
congenital with them all; and they feed by protruding the so-called
tongue underneath the operculum. The tongue of the murex is bigger
than one's finger, and by means of it, it feeds, and perforates
conchylia and the shells of its own kind. Both the murex and the ceryx
are long lived. The murex lives for about six years; and the yearly
increase is indicated by a distinct interval in the spiral convolution
of the shell.
The mussel also constructs a honeycomb.
With regard to the limnostreae, or lagoon oysters, wherever you
have slimy mud there you are sure to find them beginning to grow.
Cockles and clams and razor-fishes and scallops row spontaneously in
sandy places. The pinna grows straight up from its tuft of anchoring
fibres in sandy and slimy places; these creatures have inside them a
parasite nicknamed the pinna-guard, in some cases a small carid and in
other cases a little crab; if the pinna be deprived of this
pinna-guard it soon dies.
As a general rule, then, all testaceans grow by spontaneous
generation in mud, differing from one another according to the
differences of the material; oysters growing in slime, and cockles and
the other testaceans above mentioned on sandy bottoms; and in the
hollows of the rocks the ascidian and the barnacle, and common
sorts, such as the limpet and the nerites. All these animals grow with
great rapidity, especially the murex and the scallop; for the murex
and the scallop attain their full growth in a year. In some of the
testaceans white crabs are found, very diminutive in size; they are
most numerous in the trough shaped mussel. In the pinna also is
found the so-called pinna-guard. They are found also in the scallop
and in the oyster; these parasites never appear to grow in size.
Fishermen declare that the parasite is congenital with the larger
animal. (Scallops burrow for a time in the sand, like the murex.)
(Shell-fish, then, grow in the way above mentioned; and some
of them grow in shallow water, some on the sea-shore, some in rocky
places, some on hard and stony ground, and some in sandy places.) Some
shift about from place to place, others remain permanent on one
spot. Of those that keep to one spot the pinnae are rooted to the
ground; the razor-fish and the clam keep to the same locality, but are
not so rooted; but still, if forcibly removed they die.