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
testaceans.
17
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.
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