Bibliographical Notices. 1.37 



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

 real nature of Chroolepiui cannot be said to bo yet ascertained. The 

 plants composing the genus were fc«Tnerly regarded, sometimes as 

 Fungi, sometimes as Alga) ; and it was thought*, when Caspary dis- 

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

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

 posing that some of the species (and if some, perhaps all) are 

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



Of the Chcetophore'i' (Family 7), the most remarkable genera 

 are Chivtopltora, DrapaniaHia (^Stit/eochnium is almost identical 

 with it), Coh'OcJuete, and Apha nocJnete , to which latter genus Dr. 

 Rabenhorst (in the text, p. 3SJ1) refers the very curious plant 

 Oihlocfuete h>/sirix, which was discovered by Mr. Thwaites in fresh- 

 water ditches near Bristol uiKni the leaves of mosses, and by the 

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

 "NVareham iu Dorsetshire. The plant is beautifully figured in Dr. 

 Harvey's ' Phycologia Britannica' (pi. 22(5). He suggests that the 

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

 panxaldia is a geniLs which has not been allowed to pass un- 

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

 actions of the Liuuean 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 

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

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

 moss. 



The Melanophijcea;, which constitute the fourth class in this work, 

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

 cladia lacustris, A. Braun, remarkable for its zoospores, which are 

 produced in two different ways. The cells producing them are 

 called trichosjjoranr/ia and zoosporangia. The latter are single 

 cells from which the zoospores are produced in a mass, by division 

 of the cell-contents in the usual way. The trichosporangia 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, irake their way out through the ruptured apical cell of the 

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

 losKS, 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 Y.), the RhodopJnjceie. 

 This is divided into five families : — 1. Porjyhi/raceee; 2. Chnntransi- 

 acece; 3. Batrachosp>ermac€CB ; 4. Hildenbrandtiacece ; and 5. Le- 

 maneacece. 



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

 marine) are Porphgndium, Xag., and Bangia. The former is the 

 old PahneUa cnienta of Agardh. The two principal species of 

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



• Regensb. Flora, 1858. Micr. Joum. vol. viii. p. 159. 

 Ann. d: Mag. X. Hist. Ser. 4. Vol.y. 10 



