packed filaments, a roundish mass of minute spores spread upon a hemi- 
spherical central placenta. The ¢etraspores are scattered over the whole 
surface of the plant which produces them, and are mostly triangularly 
divided. Colour a dull purple, becoming greenish on exposure. 
ORR 
aoe 
I am indebted to M. Lenormand for having pointed out to 
me the identity between the Rhodomenia polycarpa of Greville, 
and the older Pucus multipartitus of Clemente, which Greville 
includes in his genus Chondrus ; and also for a suite of beautifully 
preserved specimens, showing the changes which this most 
variable plant assumes, according to the circumstances under 
which it grows; and I have had the additional advantage of 
consulting, im the Herbarium of Mrs. Griffiths, an authentic spe- 
cimen of Fucus multipartitus, from Cadiz, which is in all respects 
similar to some of our British mdividuals. Prof. J. Agardh, 
while he transfers the Rhod. polycarpa and Chondrus multipartitus 
of Greville to the reformed genus Gracilaria, retains both species. 
With respect to the Mucus eruginosus of Turner, which I had 
been in the habit of regarding as the typical state of G. mu(ti- 
partita, and which I had hitherto looked upon as truly distinct 
from our British 2. polycarpa: a more careful examination and a 
comparison of multitudes of specimens from very distant parts of 
the world, induce me now to regard this as merely a variety origi- 
nating probably from the plant’s growing in rougher water, beyond 
the influence of the estuaries ; and consequently acquiring a firmer 
texture, and narrower segments: the marginal processes are com- 
mon to all the varieties. A still more remarkable form of this 
species is Agardh’s var. 6. angustissimus, of which specimens have 
been kindly sent to me by Prof. J. W. Bailey, of New York, who 
obtained them at Providence, Rhode Island, where vast quan- 
tities of this variety grow on sandy bottoms. These specimens 
are quite as slender as Gracilaria confervoides, and nearly cylin- 
drical, excessively divided, and forming bushy tufts. But that 
the very narrow ones are mixed with others, which show a 
decided return to the common form of the species, one would 
never suspect them to belong to it; yet some are covered with 
the characteristically abundant tubercles. Mr. Hore has found 
at Plymouth, as Mrs. Griffiths informs me, specimens almost 
equally narrow. 
Fig. 1. GRACILARIA MULTIPARTITA :—xatural size. 2. A portion, showing the 
pitted appearance of the surface :—slightly magnified. 3. Section of frond 
and tubercle, to show the structure of both. 4. Spores from the tubercle. 
5. Tetraspores. 6. Section of a thicker portion of the frond :—all highly 
magnified. 
