92 
THE SEAWEEDS 
Dictyotla polyclada Kuetzing. 
Frond small, supradeeompound, below linear, with lateral fastigiate- 
dichotomous pinnae ; segments numerous, very short, close together, 
capillary, patent. 
Spencer Gulf, collected by Tepper. 
PACHYDICTYON J. Agardh. 
Frond like that of a very narrow Dictyota, but consisting in 3 strata 
of cells, an inner of large empty cells in one layer, from margin to margin, 
an intermediate of several layers of similar rounded-angular cells, and an 
outer of a single layer of small coloured cells. Fructification only observed 
in one species. 
Pachydictyon furcellaium (Harv.) J. Agardh. 
Frond very narrow, regularly repeatedly dichotomous, the axils wide, 
the laciniae patent, to 25 cm. long and 2 mm. wide. 
On both sides of Encounter Bay, Western Australia. 
Pachydictyon paniculatum J. Agardh. 
Frond subpinnate, subfastigiate, with broad axils, segments very narrow, 
zoned at the apex. Sori occupying a longitudinal line in the middle of 
the frond. 30 cm. or more high and little more than 2 mm. wide. 
Western and South Australia, Victoria, Tasmania. 
DILOPIIUS J. Agardh. 
Resembling Dictyota but constituted of two strata, the interior of 2 or 
more layers of squared colourless empty cells, and the outer of a single 
layer of small coloured cells. Spores scattered or in minute sori. 
Of the eleven species found in Australia, two only have been recorded 
from South Australia. 
DiJophus marginatus J. Agardh. 
Frond caespitose, attached by radicles to shells or stones near low water 
mark, decompound dichotompus with linear erect segments, the terminal 
rounded obtuse. To 9 cm. high. The adult fronds are marked with con- 
spicuous transverse wrinkles. Small spores grouped in quadrate sori 
arranged in a broad broken median series. The margins of the frond are 
thickened, the inner stratum of the lamina there consisting of four layers. 
South Australia, Victoria to Twofold Bay in New South Wales. 
