Bibliographical Notices. 137 



and Bnlhotrirhia. Of the latter little seems to be known ; and the 

 real nature of CJwooJepus cannot be said to be yet ascertained. The 

 plants composing the genus were formerly regarded, sometimes as 

 Fungi, sometimes as Algae ; and it was thought, when Caspary dis- 

 covered the zoospores of C. aureus, that its place was fixed with 

 the Algae*. After all, however, there seem to be grounds for sup- 

 posing that some of the species (and if some, pei'haps all) are 

 nothing more than peculiar states of the germ-filaments of mosses. 



Of the Chce'.ophorem (Family 7), the most remarkable genera 

 are ChcetopJiora, Draparnaldia (^Stigeocloniwm is almost identical 

 with it), Coleoclicfte, and Aphanocluete, to which latter genus Dr. 

 Rabenhorst (in the text, p. 391) refers the very curious plant 

 Ochlochoete hijstrix, which was discovered by Mr. Thwaites in fresh- 

 water ditches near Bristol ui^ou the leaves of mosses, and by the 

 Kev. W. Smith on the stems of grasses, in brackish water, near 

 Wareham in Dorsetshire. The plant, is beautifully figured in Dr. 

 Harvey's ' Phycologia Britannica' (pi. 22G). He suggests that the 

 freshwater and the brackish-water forms may be distinct. Dra- 

 parnaldia is a genus which has not been allowed to pass un- 

 challenged. Dr. Hicks, in a paper published in the ' Trans- 

 actions of the Liunean Society,' and in another paper very recently 

 read before the same Society, has suggested that Draparnaldia (or 

 some of the forms of it at least) may be only states of the germ- 

 filaments of mosses. It seems certain, however, that Draparnaldia 

 glomerata produces resting spores, and this seems to point to some- 

 thing higher than the transitory condition of a germ-filament of a 

 moss. 



The MelanopJiycece, which constitute the fourth class in this work, 

 will not detain us long ; for the only freshwater plant is PI euro - 

 cladia lacustris, A. Braun, remarkable for its zoospores, which ai'c 

 produced in two different ways. The cells producing them are 

 called trichosporayigia and zoosporamjia. The latter are single 

 cells from which the zoospores are i)roduced in a mass, by division 

 of the cell-contents in the usual way. The trichospjoranriia are 

 septate threads, in each cell of which a single zoospore is produced ; 

 but these zoospores, instead of escaping each from its own parent 

 cell, make their way out through the ruptured apical cell of the 

 trichosporangium. One other plant, the well-known Fucus vesicu- 

 losus, Linn., is admitted here as an Alga " aquae submarinae," 

 being found in rivers as long as the water remains brackish. 



We have now reached the last class (Class V.), the Rhodophycecn. 

 This is divided into five families : — 1. Porphijracece ; 2. Chantransi- 

 acece ; 3. Batrachosp>ermacecB ; 4. Hildenbrandtiacece ; and 5. Le- 

 maneacece. 



The two genera in the first division (for Forjjhyra is entirely 

 marine) are Porphyridium, Nag., and Bangia. The former is the 

 old Palmella cruenta of Agardh. The two principal species of 

 Bangia, viz. B. atro-purpurea and B. fusco-purpurea, are peculiar, 



* Regensb. Flora, 1858. Micr. Jom-n. vol. viii. p. 159. 

 Ann. & Mag. N. Hist. Ser. 4. VoI.y. 10 



