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History of Animals   

accounts for the fact that the sponges found in the Hellespont are
rough and close-textured; and, as a general rule, sponges found beyond
or inside Cape Malea are, respectively, comparatively soft or
comparatively hard. But, by the way, the habitat of the sponge
should not be too sheltered and warm, for it has a tendency to
decay, like all similar vegetable-like growths. And this accounts
for the fact that the sponge is at its best when found in deep water
close to shore; for owing to the depth of the water they enjoy shelter
alike from stormy winds and from excessive heat.
Whilst they are still alive and before they are washed and
cleaned, they are blackish in colour. Their attachment is not made
at one particular spot, nor is it made all over their bodies; for
vacant pore-spaces intervene. There is a kind of membrane stretched
over the under parts; and in the under parts the points of
attachment are the more numerous. On the top most of the pores are
closed, but four or five are open and visible; and we are told by some
that it is through these pores that the animal takes its food.
There is a particular species that is named the 'aplysia' or the
'unwashable', from the circumstance that it cannot be cleaned. This
species has the large open and visible pores, but all the rest of
the body is close-textured; and, if it be dissected, it is found to be
closer and more glutinous than the ordinary sponge, and, in a word,
something lung like in consistency. And, on all hands, it is allowed
that this species is sensitive and long-lived. They are
distinguished in the sea from ordinary sponges from the circumstance
that the ordinary sponges are white while the slime is in them, but
that these sponges are under any circumstances black.
And so much with regard to sponges and to generation in the

Of crustaceans, the female crawfish after copulation conceives and
retains its eggs for about three months, from about the middle of
May to about the middle of August; they then lay the eggs into the
folds underneath the belly, and their eggs grow like grubs. This
same phenomenon is observable in molluscs also, and in such fishes
as are oviparous; for in all these cases the egg continues to grow.
The spawn of the crawfish is of a loose or granular consistency,
and is divided into eight parts; for corresponding to each of the
flaps on the side there is a gristly formation to which the spawn is
attached, and the entire structure resembles a cluster of grapes;
for each gristly formation is split into several parts. This is
obvious enough if you draw the parts asunder; but at first sight the
whole appears to be one and indivisible. And the largest are not those
nearest to the outlet but those in the middle, and the farthest off
are the smallest. The size of the small eggs is that of a small seed
in a fig; and they are not quite close to the outlet, but placed
middleways; for at both ends, tailwards and trunkwards, there are
two intervals devoid of eggs; for it is thus that the flaps also grow.
The side flaps, then, cannot close, but by placing the end flap on
them the animal can close up all, and this end-flap serves them for
a lid. And in the act of laying its eggs it seems to bring them
towards the gristly formations by curving the flap of its tail, and
then, squeezing the eggs towards the said gristly formations and
maintaining a bent posture, it performs the act of laying. The gristly
formations at these seasons increase in size and become receptive of
the eggs; for the animal lays its eggs into these formations, just
as the sepia lays its eggs among twigs and driftwood.
It lays its eggs, then, in this manner, and after hatching
them for about twenty days it rids itself of them all in one solid
lump, as is quite plain from outside. And out of these eggs crawfish
form in about fifteen days, and these crawfish are caught at times
less then a finger's breadth, or seven-tenths of an inch, in length.
The animal, then, lays its eggs before the middle of September, and

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