OF SOUTH AUSTRALIA. 
355 
Antithamnion divergens (J. Ag.) De Toni. 
= Callithamnion cruciatum Harvey. 
Frond caespitose, filaments erect, sparsely branched, apices densely 
ocellated; pinnules, pinnae and pinnellae opposite or verticillate, soft, the 
lower ones horizontal and distant, the upper ones close to the apices of the 
ramuli, corymbose, divergently pinnulated, the lower ones opposite, upper 
ones alternate. 
South Australia (Encounter Bay), Victoria (Sealer’s Cove), Tasmania. 
Antithamnion mucronatum (J. Ag.) De Toni. 
= Callithamnion mucronatum J. Agardh. 
Frond 10 cm. to 30 cm. long, elongate, irregular, ramuli spreading, 
strongly articulate, the younger ones with dense ocellated pinnules; pin- 
nules opposite or in groups of three, soft, the lower ones patent, 
distant, and mainly simple, the younger one grouped close to the apices of 
the ramuli, corymbose, acuminate. Tetrasporangia on the inner side of the 
pinnellae, secund, many at each articulation, cruciate. 
South Australia (Investigator Strait), West Australia, Victoria, 
Tasmania. 
Antithamnion (?) delicatulum (Harv.) De Toni. 
= Callithamnion delicatulum Harvey. 
Frond dwarf, arachnoid, primary filaments creeping, secondary filaments 
erect, sparsely branched, plumed ; plumes opposite, rising from the articula- 
tions below the apices, with fine pinnae widely spaced ; the lower pinnellae 
often opposite, the rest alternate, rising from the flexuous rachis, all 
attenuated and simple, either with one or two ramuli. 
West Australia (King George Sound). 
CROUANIA J. Agardh. 
Frond filiform, gelatinous, articulate, irregularly branched, and verti- 
oillately sub-branched at the articulations, monosiphonous, glabrous or 
fibrous ; articulations short, within the outer cortex ; sometimes the 
central axis is thick and articulate; ramuli furcate, verticillate; 
the ramelli of the verticils arcuate, curving back to the stem, covering it, 
articulations one and half times as long as broad. Cystocarps on 
the shortest ramelli, sublaterally supported, or at the apices of the 
longer ones, surrounding the ramelli, carrying globose carpospores 
within the hyaline pericarp. Tetrasporangia are formed from the changed 
ramelli, sessile, spherical and triangularly divided, sometimes oblong, and 
transversely subdivided into sections. 
Crouania australis (Harv.) J. Agardh. 
= Callithamnion attenuata var. australis Harvey. 
Frond attentuated, pyramidally branched and verticillately sub-branched, 
below moniliform, distantly verticillate ; between the nodes, hyaline, 
ecorticate, the apices of the verticils subconfluent, the verticillate ramelli 
rigid, divaricate, repeatedly tri-dichotomous, conspicuously attenuated 
towards the apices. 
South Coast of Australia, Tasmania. 
