2. D'Ukvill.£a Harvey], Hook, fil.j radice e fibris crassis demum anastomosantibus constante, stipite perbrevi valido couipresso in laminam subsolidam coriaceam apice laciniatam gradatim dilatato. Nobis in, Bond. Jburn. Bot. vol. iv. p. 249. Himanthalia D'Urvillasi, Bory ? in Buperrey Voy. Bot. p. 135. (Tab. CLXV, CLXVI.)
Hab. Hermite Island, Cape Horn, and the Falkland Islands ; abundant.
Radix fibrosus, fibris crassis, inter se intricatis, demum anastomosantibus, discum callumve pertusum 2-4 unc. diametro efficientibus. Stipes 3-4-unciabs, - f unc. diametro, valde eompressus, in laminam forma variam gradatim dilatatus. Lamina 4-8-pedabs, supra mediiun 1-2 ped. lata, pleramque late lanceolata, basi angustata, apicem versus in lacinias plures bneari-elongatas ligulatas abbreviatasve acutas tnmcatasve fissa, siccitate atro-fusca v. subpicea, opaca, dura, subfragilis, lineis superficiaUbus striata, v. subreticulata, e conceptaculis prominulis mamillosa; madore obvaceo-biimnea, coriacea v. flaccida, plana, lsevis, intus sohda, 1^1 lin. erassa. Conceptacida sphserica, per totam frondem sparsa, poro inconspicuo pertusa, fibs articulatis sporisque basiiixis repleta. Sporce ut in D.utili, varie quaternatim divisse, bmbo hyalino cinctae.
Always considerably smaller than the B. idilis, of a much thinner texture, and readily distinguishable by its fibrous root. I have never observed the frond of even the largest state of this species to be filled with those elongated transverse cells which distinguish the former.
The structure of the fronds is seen to consist, on a transverse section, of a dense narrow layer of cortical substance, which gradually becomes more open inwards, and there breaks up into parallel lanielke projecthig towards the centre of the frond. These are less densely packed inwards, and are united at right angles by similar very-short plates, together forming a loose cellular tissue, whose walls are thickened at the angles ; which, again, at the very centre of the frond, are gradually resolved into a mass of slender, short, waved filaments, free or anastomosing and floating in a gelatine.
The affinity of the Laminaria potatorum is probably with this genus; it is described, by M. Kutzing, under the generic name of Sarcophycus (Phycologia, p. 392). I have examined a very small fragment of the plant, and find the spores to be contained in cysts, altogether like those of D'Urvillaa and Xipltopliora.
Plates CLXV, CLXVI. — 1, transverse sbce of frond ; 2, vertical section of ditto ; 3, spores and antheridia; 4, spores : — highly magnified.
2. SCYTOTHALIA, G-rev.
1. Scytothaiia Jacqitinotii, Mont., in Voy. au Pole Sud, Bot. Crypt, p. 86. t. 5.
Hab. Graham's Land; lat. 63° S., floating in the ocean, I)r. Lyall. Deception Island, New South Shetlands; Mr. Webster.
An accurate description of this noble sea-weed is given by its discoverer, Mr. Webster, R.N., in the Appendix to the Narrative of Capt. Foster's Voyage; though nothing was known of the species, botanically, until specimens were received by Dr. Montagne, from the Herbarium of the French South Polar Expedition, collected within a very few miles of the spot where it was again seen by the Antarctic Expedition, and obtained by our indefatigable friend, Dr. Lyall.
The existence of this sea-weed on the Icy shores of an Antarctic land, in the longitude of Cape Horn, is a most singular and anomalous fact; for I bebeve it to be the only species of the tribe Cystosdrete, which inhabits the colder or Antarctic seas of South America; though many abound in similar temperate latitudes of New Zealand, Lord Auckland's group, New Holland, and Tasmania. We have thus, under the most rigorous skies, the representative of a group, the total absence of whose other species in warmer seas of the same longitude, was supposed to be owing to a low degree of temperatine being destructive to its life. The said group of Cystoselrece is not here represented by a species in any way indicative of its habitat being far removed from its congeners, or of its locabty being uncongenial,
