BIBLIOGRAPHY. 
125 
Bahamas. One species, M. clathratum, Mert., is removed from the 
genus and placed in that of Cystodictyon , J. E. Gray, together with 
Anadyomene Leclancherii and a new species from Florida, named 
C. pavoninum. To the genus Pterodictyon , J. E. Gray, Dr. Agardh 
refers the Struvea anastomosans of Murray and Boodle ( Cladophora 
anastomosansy Harv.) as well as the Struvea delicatula of 
Duchassaing and Maz4, as he considers that the genus Struvea 
should include only species characterized by a well-marked, 
tubular, more or less annulated stem and a lamina of definite 
outline. The danger of mistaking analogy for affinity is often 
overlooked. In a new genus of JEctocarpacece, named Xanthosi - 
plionia, the structure resembles Polysiphonia, and the greenish 
colour of the plants might suggest an affinity to the Chlorophycece , 
but the fruit is that of Ectocarpacece. In the sterile state the 
colour is greenish, like that of Ectocarpus virescens or E. viridis, 
but in the fruiting state it is yellowish. Of the two new species, 
one, X. Wattsii , comes from Australia, and the other, X. Hallice , 
from Florida. 
One new Australian species of Echionia, E. stenophylla, is 
added to the Laminar iacece, and a new genus, Encophora, to the 
Fucacece , both from Australia, but the imperfect state of the speci- 
mens received does not permit of a complete description, although 
it is sufficient to indicate that they are distinct and new. To the 
Ceramiacece have been added Antithamnion nigrescens , Spongoclo- 
nium scoparium , and S. fasciculatum, all from Australia. The old 
name Dasythamnion , being free, has been used for a new genus, 
including one new species, Dasythamnion setosum, from Australia. 
It possesses a remarkable similarity in habit to Wrangelia 
clavifera , but differs from that plant in its fructification, and in its 
more distichously pinnate ramification, and in the ramenta being 
of almost uniform diameter from base to apex. When dry the 
plant has not the blackish colour of W. clavifera, but a rufescent 
hue. A new Pallia , intermediate between B. callitricha and 
B. scoparia, is described. The specimens examined were remark- 
able for their rusty tint. 
Under Griffithsia , Dr. Agardh records the discovery of the 
antheridia of G. elongata, the characters of which vindicate his 
previous removal of the plant from the genus Callithamnion. 
Under Gulsonia, a description of the cystocarpic fruit is given, 
from which it appears that the affinity of the genus is nearer to 
Wrangelia than Crouania, near which it has been placed by Dr. 
Schmitz. A new species of Spyridia from Florida, S. ceramioides , 
is referred to the biannulate group of the genus, but has shorter 
articulations than either S. biannulata or S. breviarticulata. 
Referring to the close resemblance between Rhabdonia and 
Frythroclonium in habit and structure, Dr. Agardh observes that 
although in the sterile state it is difficult to distinguish E. 
angustatum from R. charoides or E. Mulieri from R. verticillata , 
except by the presence of a central tube in Erythroclonium , yet 
