6-20 una longee, rarius bi-tripedales, crassse, simplices v. fiircatee v. ad basin bipartite, nunc margine frondes accessorias ernittentes, interdum poris perplurimis pertusee. Superficies frondis kevis, lucida, adulta papillosa ; papillis creberrimis, tandem totam f'rondeni utrinque vestientibus, apice fructiferis, favellidia immersa poro pertusa gerentibus. Sjwra minutse, rosea?, densisshne aggregate. Spl/arospora frondibus papillarum destitutes immersa;, substrato eor- ticali sitre, in globulis minutis punctiformibus aggregata;, totam frondem pustulantes. Substantia crassa, carnosa. Color lividus, rubescens purpurascensve, raro atro-sangnineus.
There is scarcely a maritime rock on the Antarctic coasts, that does not abound with, this most protean species in all stages of growth, and bearing fronds with every variety of outline. It is much eaten by marine animals, and from this or other causes, amongst which may be reckoned the fall of the fructiferous papilla;, the plant is frequently found more or less perforated with round holes, sometimes so regularly as to resemble coarse lace: this state has been described by Kiitzing, under the name of Ckondrodictyon Capense, and by Decaisne as Iridoea clathrata (Ann. Se. Nat. Ser. III. vol. ii. p. 236). More puzzling is the form of the secondary fructification or spha;rospores, which is so like a primary fruit, that had not both Mr. Harvey and myself seen this plant growing on its native rocks, we should have supposed the individuals producing them to belong to a different species. The secondary fruit of I. stiriata is of the same nature.
The I. micans, Bory, volans, Grev., and laminarioid.es, Bory, enumerated by Montagne as natives of Lord Auckland's group, are probably states of this.
28. HALYMENIA, Agardh.
1. Halymexia hidssima, Hook. fil. et Harv.; fronde plana tenui gelatinoso-membrauacea latissime ovato-lanceolata sirnplici bifida v. margine laciniato-pinnatifida, laciniis ovato-lanceolatis acutis. (Tab. LXXIII.)
Var. /3, bifida • fronde lanceolata basi attenuata bifida v. bifurcata, laciniis lanceolatis erectis.
Hab. Lord Auckland's group and Campbell's Island ; both varieties abundant on rocks in the sea.
Frondes 2-1-1 una longse, 4-6 latse, tenues, basi cuneatae, late lanceolata; v. ovato-oblongse, acuta;, simplices v. furcatse, margine piano sirnplici integerrimo v. laciniis plurimis subpinnatifido. Substantia gelatiuosa. Favellidia numerosissima, per totam frondem sparsa, cellulis medullaribus immersa. Color amasne roseus.
We offer this as a new species with some doubt, the varieties of H. ligulata approaching it. The fronds are so broad and thin, that the favellidia form convexities on its surface, which are more or less obliterated when moist.
Plate LXXIII. Fig. 1, portion of the surface of the frond ; 2, section of the same ; 3, spores : — all magnified.
29. DUMONTIA, Lamour.
1. DuiioXTiA fil "iformis, Grev., Alg. Brit. p. 165. t. 17. Halymenia, Agcirdh Sjyec.Alg. vol. i. p. 214.
Hab. Campbell's Island. (Dr. Lyall.)
Identical with the European plant. Found also at the Cape of Good Hope and in other widely separated localities.
2. Dumontia cornuta, Hook. fil. et Harv.; fronde tubulosa hie ilh'c inflata clivisa, parte inferiore nudiuscula superiore rarnis confertis fasciculatisve quacirifarhs vestita, rarnis furcatis patentibus flexuosis alternatim rarnulosis, ramulis recurds utrinque attenuatis apicibus acutis.
Hab. Campbell's Island. (Br. Byall.)
Frondes crespitosa;, 2-3 una longre, tubulosa;, irregulariter inflata;, 2 lin. lata;, vage divisa; ; rarnis intricatis, patentibus, flexuosis, furcatis ; ramulis fusiformibus, patentibus v. recurvis. Color fuscatus, bacbus v. rubescens.
Our specimens of this plant are barren; we refer it to Dumontia from the tubular inflated frond, structure, and habit.
