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rosy-pink ; wlien dry it fades to a yellowish ; and when exposed to the
sun becomes perfectly white, and rapidly cnimbles to powder. Under the
microscope, a longitudinal section (when the calcareous matter has been
removed by acid) shows a series of concentrical zones, formed of oblong
cells separated by narrow spaces, filled with gramdar cellules, or possibly
tbe appearance of bands may arise from tbe remains of calcareous matter.
Fig. 3. represents a section of this description.
I follow Decaisne in referring the Nulliporoe of Lamarck to
the Melohesioe of Lamouroirx, the latter name having been generally
adopted by such botanists as have described these productions,
and the former by sirch zoologists as lay claim to them.
Both names originated in 1816, and whichever have priority, it
must be a narrow question of months, wbicb I am unable to
decide. Tbe species here figured would belong to Spongites of
Kützing, fo\A to Lithophgüum of Philippi; but does not appear
in the list of Melobesia given by Decaisne, nor yet, except under
the more modern trivial name, decussata, in that of Lndlicher.
Nevertheless it is one of the earliest known species, as its numerous
synonymes testify.
The question of the vegetable nature of Corallines, among
which the Melobesia take rank, may now be considered as
finally set at rest, by the researches of Kützing, Philippi, and
Decaisne, whose various memoirs, particularly that of the last
named, have thrown much light on this obscure department
of natural history, and fully confirmed tbe early views taken
by Peyssonel, the elder Jussieu, Pallas, &c., in opposition to
those of Lllis and most succeeding authors, who have associated
them with the zoophytes. Outwardly, indeed, there is a striking
resemblance, not less in form than in substance, between the
Corallines and Corals ; but it is merely an outward resemblance.
Whoever macerates a portion of one of these stony vegetables
in weak acid, till the lime it contains be dissolved, will find, that
he has a structure of a totally different nature from that of any
zoophyte, while it is perfectly analogous to tbat of many Algæ.
There is a near affinity, indeed, between tbe Corallina and the
Rhodomelea ; or perhaps still more, the Condriea.
Fig. 1. M e l o b e s i .a a g a r ic i f o r m i s : — the natural size. 3. Portion of a
lamina, with some of its epidermis removed, showing the banded arrangement
of the cellules :— slightly magnijied. 3. Longitudinal section of the
same :— highly magnijied.
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