In Tierra del Fuego, as well as in the Falkland Islands, made many
observations on the lower marine animals, [11] but they are of little
general interest. I will mention only one class of facts, relating to
certain zoophytes in the more highly organized division of that class.
Several genera (Flustra, Eschara, Cellaria, Crisia, and others) agree
in having singular moveable organs (like those of Flustra avicularia,
found in the European seas) attached to their cells. The organ, in the
greater number of cases, very closely resembles the head of a vulture;
but the lower mandible can be opened much wider than in a real bird's
beak. The head itself possessed considerable powers of movement, by
means of a short neck. In one zoophyte the head itself was fixed, but
the lower jaw free: in another it was replaced by a triangular hood,
with beautifully-fitted trap-door, which evidently answered to the
lower mandible. In the greater number of species, each cell was
provided with one head, but in others each cell had two.
The young cells at the end of the branches of these corallines contain
quite immature polypi, yet the vulture-head attached to them, though
small, are in every respect perfect When the polypus was removed by a
needle from any of the cells, these organs did not appear in the least
affected. When one of the vulture-like heads was cut off from the
cell, the lower mandible retained its power of opening and closing.
Perhaps the most singular part of their structure is, that when there
were more than two rows of cells on a branch, the central cells were
furnished with these appendages, of only one-fourth the size of the
outside ones. Their movements varied according to the species; but in
some I never saw the least motion; while others, with the lower
mandible generally wide open, oscillated backwards and forwards at the
rate of about five seconds each turn, others moved rapidly and by
starts. When touched with a needle, the beak generally seized the
point so firmly, that the whole branch might be shaken.
These bodies have no relation whatever with the production of the eggs
or gemmules, as they are formed before the young polypi appear in the
cells at the end of the growing branches; as they move independently of
the polypi, and do not appear to be in any way connected with them; and
as they differ in size on the outer and inner rows of cells, I have
little doubt, that in their functions, they are related rather to the
horny axis of the branches than to the polypi in the cells. The fleshy
appendage at the lower extremity of the sea-pen (described at Bahia
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