IV. 
DICTY 0TACE2E. — Dictyosiphon. 
113 
Plate IX. B. Fig. 1 . Frond of Stilopiioea rhizodes , the natural size ; ftg. 2, a 
small portion of a branch, with its wart-like sori, magnified ; fig. 3, section of a 
sorus, and of a portion of the frond ; fig. 4, a spore and paranema ; the latter 
figures highly magnified. 
2. Stilophoka papillosa, J. Ag. (?) ; frond cylindrical, many times dichotomous, 
with very patent angles and divaricating, attenuated apices ; the dichotomous 
branches and their lesser divisions clothed with very many slender diorizontal, hair- 
like ramuli. J. Ag. Sp. Alg. vol. 1 : p. 84. (?) 
Hab. Chesapeake Bay, Prof. J. W. Bailey, (v. s.). 
I am not satisfied that the plant from the Chesapeake, which I introduce more on 
my friend Prof. Bailey’s authority than my own, is the same as the Mediterranean 
species described by Agardli ; nor, indeed, am I quite certain that it belongs to 
this genus. I have examined one of the original specimens, presented to me by 
Prof. Bailey, and had intended figuring it, but have not been able to make out the 
microscopical characters to my satisfaction. The above specific diagnosis applies 
very well to the specimen. But Meneghini’s figure, {Alg. Ital. t. 3, /. 2,) quoted 
by Agardh for his species, is very unlike our plant. I have seen no authentic example 
of the Mediterranean S. papillosa , and thus am unable fully to decide on the 
identity of the American ; and, in this uncertainty, think it better to place the 
species on record, in the hope that future observation may clear the subject in one 
way or other. My specimen is about four inches square in the spread of the 
branches, and it scarcely adheres to the paper on which it has been dried. 
VII. DICTYOSIPHON. Grev. 
Boot a small, naked disc. Frond filiform, tubular, much branched ; its walls 
composed of several rows of cells, of which the inner are elongated, and connected 
into longitudinal filamentous series ; the outer or superficial small, coloured, poly- 
gonal, forming a membrane. Fructification : solitary or aggregated, naked spores , 
scattered irregularly over the surface. 
When young the frond is solid, but the cells forming the axis, which are of 
larger size than the rest, are also weaker and soon perish, leaving the stem and 
branches fistular. In a growing state every branch is clothed with long, slender, 
pellucid, jointed hairs, which give the plant, when seen under water, a beautifully 
feathery character. Similar hairs are seen on many others of the Order, and are 
doubtless connected with the development of the frond. The walls are composed 
vol. in. akt. 4. Q 
