HtcTf. niL£).
P l a t e LXXIV.
MELOBESIA FASCICULATA, llm v .
Gen Chae. Frond attached or free, either flattened, orbicular, sinuated or
irregularly lobed, or cylindrical and branched (never articulated),
coated with a calcareous deposit. Fructification-, conical, sessile cap-
sules [ceramidia) scattered over the surface of the frond, and containing
a tuft of transversely parted, oblong tetraspores. M e l o b e s i a [Lamour.)
—from one of the Sea nymphs of Hesiod.
yL-EwmsiK fa sc iculata-, frond unattached, ronndish or lobed, stoney, much
branched, fastigiate; branches solid, thick, crowded together, cylindrical
or compressed; apices truncate, broad, somewhat concave.
M i l l e p o r a fasciculata, Lam. An. s. vert. vol. ii. p. 303. 2nd. M it. p. 211.
N e l l ip o r a fasciculata, BUinv. Actin. p. 605. Jolimt. Br. Spon. and Lith.
p. 240. t. 24. f. 6.
L i t h o t i i a m n i u m crassum, Phil, in Wieg. Arch. 1837. p. 388 ?
H ab. Lying on the sandy bottom of the sea, in 4 -5 fathom water. Eound-
stone Bay, M f. Me’ Calla,
G e o g r . D i s t r . Atlantic and Mediterranean stores of Europe.
D e s c r .' Fronds from one to three inclies in diameter, roundish or irregularly
lobed, composed of a solid central stony mass of no determinate form or
size from which issue in all directions numerous short, thick, cylindrical or
laterally compressed, crowded branches divided in an irregularly dichotomous
manner, all nearly fastigiate, and remarkably truncated at the tips, which
are moreover depressed in the centre. These broad, flattened or subconcave
tins ai-e the least variable character of the species. In other respects it is
subiect to much variety. Sometimes the branches are reduced to mere
rudiments or very much flattened; and sometimes the frond presents little
else than an aggregate of thickened tabular pieces. The colour when recent,
is a livid purple; when dried, it fades to a du-ty white. Under the micro-
scone after the calcareous matter has been removed by acid, a longitudinal
section shows a fibrous surface, marked here and there by obscme zones;
and a transverse cutting exhibits a radiate arrangement of the ceUs. _ Under
a lens of hi»h power, the fibres resolve themselves into delicate, jointed,
slightly moniliform filaments, easily separating one from anoteer, toward
the sm-face, but massed together into an irregularly ceUular substance, at a
greater depth within the frond.
This species would fall under the genus Litlioihamnium of
Philippi, if it ho not the same that he has described by the name
L. crasmm. I think it must be by a slip of the pen that Decaisne
unites these plants to AmpUroa, from which genus they differ in