The Cambridge natural history, Vol. 01 (of 10)Hickson, Sydney J. (Sydney John)
Science
The Cambridge natural history, Vol. 01 (of 10)
Hickson, Sydney J. (Sydney John)
Animals
Sponges figure in herbals beside seaweeds and mushrooms, and Gerarde
says:[187] "There is found growing upon rockes near unto the sea a certaine
matter wrought together of the foame or froth of the sea which we call
Spunges ... whereof to speak at any length would little benefit the reader
... seeing the use thereof is so well known." About the middle of the
eighteenth century, authors, especially Peyssonnel, suggested that sponges
were but the houses of worms, which built them much as a bee or wasp builds
nests and cells. This was confuted by Ellis in 1765,[188] when he pointed
out that the sponge could not be a dead structure, as it gave proof of life
by "sucking and throwing out water." To Ellis, then, is due the credit of
first describing, though imperfectly, a current set up by sponges. He
mentions that Count Marsigli[189] had already made somewhat similar
observations.
It was not till 1825 that attention was again turned to the current, when
Robert Grant approached the group in a truly scientific manner, and was
ably supported by Lieberkühn. It would be impossible to do justice to Grant
in the brief summary to which we must limit ourselves. The most important
of his contributions was the discovery that water enters the sponge by
small apertures scattered over the surface, and leaves it at certain larger
holes, always pursuing a fixed course. He made a few rough experiments to
estimate the approximate strength of the current, and, though he failed to
detect its cause, he supposed that it was probably due to ciliary action.
Grant's suggestion was afterwards substantiated by Dujardin (1838), Carter
(1847), Dobie (1852), and Lieberkühn (1857). These five succeeded in
establishing the claims of sponges to a place in the animal kingdom, claims
which were still further confirmed when James-Clark[190] detected the
presence of the protoplasmic collar of the flagellated cells (see pp. 171,
176). Data were now wanted on which to base an opinion as to the position
of sponges within the animal kingdom. In 1878 Schulze[191] furnished
valuable embryological facts, in a description agreeing with an earlier one
of Metschnikoff's, of the amphiblastula larva (p. 226) and its
metamorphosis. {168}Then Bütschli[192] (1884) and Sollas[193] on combined
morphological and embryological evidence (1884) concluded that sponges were
remote from all the Metazoa, showing bonds only with Choanoflagellate
Protozoa (p. 121). This the exact embryological work of Maas, Minchin, and
Delage has done much to prove, but it has to be admitted that unanimity on
the exact position of the phylum has not yet been attained, some
authorities, such as Haeckel, Schulze, and Maas still wishing to include
sponges in the Metazoa.
In this short history we have been obliged to refer only to work helping
directly to solve the problem of the nature of a sponge, hence many names
are absent which we should have wished to mention.
HALICHONDRIA PANICEA.
Public-domain text, read in full here on John Shaqi.
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