Ser. RHODOSPERME. Fam. Corallinee ? 
Puate CCL. 
HILDENBRANDTIA RUBRA, Jfeney. 
Gen. Cuar. Frond cartilagineo-membranaceous, (zo¢ stony,) crustaceous, 
suborbicular, adhering by its lower surface ; composed of very slender, 
closely packed, vertical filaments.  Conceptacles immersed in the 
frond, orbicular, depressed, pierced by a hole and containing tetra- 
spores and paraphyses at the base of the cavity. H1LpENBRANDTIA 
(Nardo),—in honourof . . .... ? 
Hitpensranptia rubra, Meneg. 
HriLpENBRANDTIA rubra, Meneg. Mem. Riun, Nat. Padov. 1841, p.10. Endl. 
3rd Suppl. p. 26. (eacl. Syn. Berk.) Kiitz. Phyc. Gen. p. 384. t. 78. f. V. 
HitpEensBranpira Nardi, Zanard. Alg. Adr. p. 135. 
Ruopopermis Drummondii, Harv. in Ann. Nat. Hist. vol. xiv. p. 27. pl. 2. 
Has. On smooth stones and pebbles, between tide-marks, as well as in 
deep water. At all seasons? Common on the shores of the British 
Islands. 
GrocGr. Distr. Atlantic and Mediterranean shores of Hurope. 
Descr. Frond forming a thin, crustaceous expansion from half an inch to two 
inches or more in diameter, at first orbicular, and spreading in concentrically 
marked patches, but gradually sinuated and its surface irregularly cor- 
rugated as it advances in age; closely adhering by the whole of its under 
surface to the rock or stone on which it grows. <A small portion viewed 
vertically with the microscope shows innumerable dot-like cells, imbedded 
in a clear, firm, gelatine: and, thin slices, viewed laterally, prove the crust 
to be formed of very densely set, and closely cohering, slender filaments, 
composed of minute cells. When in fruit the surface is pitted with disc-like 
depressions, pierced in the centre by a hole which communicates with a 
chamber or immersed conceptacle hollowed out of the frond, and containing 
a few oblong, zoned tetraspores, among a number of paraphyses or abortive 
filaments. The part of the frond forming the walls of the conceptacle is 
of a much paler colour than the rest. Colour varies, according to locality, 
from a clear blood-red to a dark red brown. Substance coriaceo-membra- 
naceous, very firm. 
Common all round the coast, on stones and rocks within 
tide-marks, and also often dredged from deeper water. It forms 
a thin skin-like film, so closely applied to the surface of the body 
on which it grows that it is impossible to remove a specimen 
