459 ALGÆ OF TASMANIA. 
in part.—Frond 6-8 inches high, setaceous below, exces- 
sively branched in a regularly pinnate manner, each succes- 
sive pinnation being more slender than the last, till at the 
fifth or sixth the diameter is reduced to that byssoid fineness 
that requires a strong magnifying power to see it clearly. 
The scheme of branching is obviously -by opposite patent 
branches or pinnze, repeated over and over again; but from 
some cause it happens that in by far the greater number of 
cases in the earlier development of the frond, one of these 
branches is either very much shorter than the other, or is 
reduced to a mere rudiment, or even altogether wanting; 
though its place is usually found occupied bya small ramulus, — — 
The main branches, and their divisions therefore are fre- 
quently alternate. The structure of the stem is peculiar, and 
something at variance with the genus, while it shows a transi- — 
tion to Crouania or Dudresnaia. It is composed of a bundle 
of fine longitudinal threads, glued together, and as if knotted 
or more firmly combined together at each joint or node from | 
which the branches issue. In old parts it is wholly covered 
with short hair-like ramelli, but in younger parts these are 
confined to the nodes, which are 2 or 3 diameters apart from 
each other. This nodose structure is found in all the di- 
visions till we come to the last where the frond is reduced to 
a byssoid fineness and a single tube. The last or extreme 
nodose-pinnules, besides the hair-like ramelli that clothe the 
nodes, throw out at each node a pair of opposite slender Z 
byssoid pinnulated ramuli, whose pinnules are either alter- — 
nate or secund, erecto-patent, and bear along their upper ae 
face, from joint to joint, a row of pedicels, each of which 
supports a spherospore. Joints of the ramuli 4 times longer — 
than broad. Colour a fine rosy red, not soon changing ™ — 
fresh water, and well preserved in drying. Substance very 
tender and lubricous.—A noble species, and not likely to be 
confounded with any other. - — o 
43. Callithamnion latissimum, Harv. ; caule elongato, frondem 
percurrente, tenui, basi opaco, subsetoso, e fibris consti- : 
tuto, in parte superiore articulato glabro ; fronde latissimâ, 
pluries pinnatâ, divisionibus omnibus alternis; ramis ] 
