tibus oblongis cuneatis rariusve clliptico-lanceolatis costa furcata, soris rotundatis rnaculatis, eoccidiis costalibus v. sparsis. (Tab. LXXI. Fig. II.)
Hab. Lord Auckland's group and Campbell's Island. (Br. Lyall.)
Frons junior, folium obovatum, obtusum v. emarginatum, demum bilobum ; costa furcata, demum repetito-dichotoma, deorsum crassa, sursiun attenuata, sub apicem evanida. Frondes adultas caulk furcatus v. dichotomus, 2-3 unc. longus, setae porcinse crassitie, nudus v. interruptim alatus, supeme in frondes cimeatas v. dichotomas abeuns j inferne denudatus v. frondibus novis primordiali conformibus sed angustioribus minusque cuneatis ornatus, hie 1-j unc. lougse, costis supra medium furcatis fructiferis. Coccidia in laminam rarius in costam sita, sphaerica, sparsa, granulis cuneatis repleta. Sori sph<erosporarum rotundati, supra laminam dispersi. Substantia membranacea. Color purpureo-roseus v. sanguineus. — Chartae adhaeret.
When fully grown, this species resembles a very broad and luxuriant state of D. alata, found in the north of Ireland, but differs essentially from it in its mode of growth. Judging by young specimens, it appears to originate in a broadly ovate or cuneate leaf, traversed by a forked, or, as the frond advances, repeatedly dichotomous midrib, which, though gradually evanescent, is obvious for nearly the whole length of the lamina, and thus differs from the imperfectly branching veins of the Nitophylla. In old and battered specimens, however, this character can only be detected in the young parts ; in them, the costa of the first formed leaf becomes denuded, considerably thickened and converted into a dichotomous stem, irregularly winged in portions, and only preserving, on the upper part, the remains of its former character; while, all along its denuded portions, spring numerous new fronds, narrower than that which forms the principal one, and less cuneate, but in other respects simdar.
Plate LXXI. Fig. II. — 1, 2, and 3, specimens in different states, of the natural size; 4 and 5, coccidia; G and 7, sphaerospores : — magnified.
18. NITOPHYLLUM, Grev.
1. Nitophyllum crispatwm, Hook. fil. et Harv.j fronde basi nervosa cuneata latissime expansa v. oblonga dicliotoma v. laciniata margine crispata, nervis rarnosis, laciniis cuneatis apicibus axillisque obtusis, soris minutis rotundatis coccidiisque sparsis. (Tajb. LXXI. Kg. I.)
Hab. Campbell's Island ; dredged up in three fathoms water. Two specimens, one with capsular, the other with granular fruit, we refer to this species. The capsuliferous specimen bears a very great resemblance to the north of Ireland variety of N. laceratum ; the gramdiferous, again, has more the oblong form of N. punctatum. Both agree in being traversed, especially in the lower part, with obscure dichotomous nerves, in having the margin crisped, and exhibiting a tendency to dichotomous division. The scattered granular fructification essentially distinguishes it from N. laciniatum, and the form and size of the spots, from N. punctatum.
Plate LXXI. Fig. I. — 1, 2, and 3, specimens of the natural size ; 4, coccidia ; 5, sphaerospores : — magnified.
2. Nitophyllum punctatum'? Grev. Alg. Brit. p. 79. t. 12. Agardh, Species Alg. vol. i. p. 186. Aglaophyllum, Montague in Plant Cell. Canar. p. 150.
Hab. Campbell's Island ; with the former.
Decayed fragments, which appear to belong to this species, are all that were procured.
19. PLOCAMIUM, Byngb.
Obs. The genera Thamnophora and Flocamium appear to differ in no respect from each other, and so perfectly
