360 
THE SEAWEEDS 
alternate, about 1mm. long, patent, broadly subulate, subacute, with blunt 
axils. The whole frond is tubular and hollow, but compressed. The tube 
is traversed by a pointed, monosiphonous, coloured, filamentous axis, at each 
joint throwing out a whorl of repeatedly dichotomous, horizontal, fastigiate 
ramelli, whose extremities alone anastomose, and form the enveloping mem- 
brane which constitutes the covering of the frond. Colour dark or 
brownish-red. Substance soft ; adheres to paper. Cystocarps acrogenous, 
forming in the clavate 1 ramuli, often singly, wholly corticate. Tetraspor- 
angia carried on the proliferous ramuli, often at the apices, large in 
proportion to the size of the plant, triangularly divided. 
West Australia (Rottnest Island), Victoria ( Warrnambool) . 
PT1LOCLADIA Sonder. 
Fronds .compressed, pinnately decompound, sponge-like, formed of 
dichotomous, articulate, interwoven anastomosing ramelli, issuing from a 
central articulated axile filament; the apices of the ramelli fastigiate, 
forming the periphery of the frond. Favellae binate, immersed in the 
ultimate divisions of the frond. Tetraspores tripartite, attached to the 
peripheric ramelli. 
Ptilocladia pidchra Sonder. 
Frond compressed, pinnately decompound, sponge-like, formed of dicho- 
tomous, articulate, interwoven (and anastomosing ?) ramelli, issuing from 
a central articulated axile filament; the apices of the ramelli fastigiate, 
forming the periphery of the frond. Favellae binate, immersed in the 
ultimate divisions of the frond. Tetraspores tripartite, attached to the 
peripheric ramelli. 
Attachment or holdfast a mass of interwoven fibres. Frond 10 cm. to 
15 cm. high, 2 mm. to 6 mm. broad, .compressed, distichously much branched ; 
branches irregular, but in a more or less pinnate order ; some specimens 
several times compounded and closely branched ; others distantly branched. 
The texture of the frond is sponge-like, composed of a central, articulated 
filament or axis, which emits from the centre of every joint numerous small 
horizontal ramelli. These ramelli are dichotomous, many times forked, 
their branches closely interlaced together into the spongy mass of the frond. 
The ramelli forming the shorter diameter (in section) of the compressed 
frond are simply dichotomous; those that form the longer diameter have 
a simple rachis, pinnated with dichotomous branches. Favellae in structure 
quite like those of Callithamnion , borne in special processes of the frond 
which stand out from the smaller pinnules, each on a short pedicel; but 
these processes are of the ordinary composition of the frond, though homo- 
logically to be considered as involucres. Tetrasporangia immersed among 
the peripheric ramelli of other fronds, attached singly, here and there, 
near the apex of the ramellus. Colour deep red; substance soft, spongy, 
when old dry and rigid. Adheres to paper. 
South Australia (Eastern Bays), West Australia. 
