Ser. RuoposPpeRME”. Fam. Corallinee. 
Puate LXXIV. 
MELOBESIA FASCICULATA, Hav. 
Gen. Cuar. 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. Mntosusta (Lamour.) 
—from one of the Sea nymphs of Hesiod. 
Mexosesta fasciculata; frond unattached, roundish or lobed, stoney, much 
branched, fastigiate ; branches solid, thick, crowded together, cylin- 
drical or compressed ; apices truncate, broad, somewhat concave. 
Miterora fasciculata, Lam. An. s. vert. vol. i. p. 208. 2nd. Edit. p. 211. 
Nuxiipora fasciculata, Blainv. Actin. p.605. Johnst. Br. Spon. and Lith. 
p- 240. t. 24. fi 6. 
LirHoTHAMNIUM crassum, Phil. in Wieg. Arch. 1837. p. 388? 
Has. Lying on the sandy bottom of the sea, in 4—5 fathom water. Round- 
stone Bay, Mr. Me’ Calla. 
Geogr. Distr. Atlantic and Mediterranean shores of Europe. 
Descr. Fronds from one to three inches 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 
tips are the least variable character of the species. In other respects it is 
subject 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 dirty white. Under the micro- 
scope, after the calcareous matter has been removed by acid, a longitudinal 
section shows a fibrous surface, marked here and there by obscure zones ; 
and a transverse cutting exhibits a radiate arrangement of the cells. Under 
a lens of high power, the fibres resolve themselves into delicate, jointed, 
slightly moniliform filaments, easily separating one from another, toward 
the surface, but massed together into an irregularly cellular substance, at a 
greater depth within the frond. 
— 
a 
This species would fall under the genus Lithothamnium of 
Philippi, if it be not the same that he has described by the name 
L. crassum. \ think it must be by a slip of the pen that Decaisne 
unites these plants to Amphiroa, from which genus they differ in 
