variety of characters assigned to it by the several authors who 
have taken it up. Even those who agree in making B. fusco- 
purpurea the typical species, describe its structure very diffe- 
rently ; some asserting that this plant is flat, others tubular but 
plano-compressed, and others cylindrical. That the latter is its 
true character becomes at once evident, by making a transverse 
section of a filament, or, as is much more easily done, by cutting 
a half dry bundle of filaments into short frustules, which, when 
moistened, will immediately exhibit the circular wheel-like ap- 
pearance, represented at our fig. 3. 
M. Chauvin, in his excellent ‘ Recherches’*, has entered at 
great length into the history of this genus, proposed a reformed 
character, and limited the species to B. fusco-purpurea (the type), 
B. crispa, B. ciliaris, and B. elegans, Chauv., the last-mentioned 
differmg from the others in having a branching frond. JB. 
Laminaria of Lyngbye, is, he assures us, identical with the 
young state Asperococcus ? pusillus, Cann., its affinity with which 
was long since pointed out by Mr. D. Moore. While I admit 
the near proximity of these plants, I am not yet prepared to 
unite them. £? letevirens, on the same authority, is only the 
rudimentary state of an Hxteromorpha; and this I am disposed 
to allow. 
A curious point in the history of Bangia fusco-purpurea is, that 
it is found equally in the sea, and in fresh-water rivers and 
canals, reaching an equal degree of development and coloration 
in either situation. Such an indifference is very unusual among 
the Algz ; but I can perceive no sufficient distinctions between 
the fresh-water and marine specimens to found a separate species 
upon. Prof. Kiitzmg, however, describes the fresh-water form 
under two names, B. coccineo-purpurea and B. roseo-purpurea ; 
relying chiefly on the habitat, and some slight difference of 
colour. I fear these species cannot stand. 
* Recherches sur organization, la fructification et la classification de plusieurs 
genres dalgues, &c.: Caen, 1842. 
Fig. 1. BANGIA FUSCO-PURPUREA :—of the natural size. 2, Portions of fila- 
ments :—magnified. 3. A transverse section of a filament :—sighly magnified. 
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