352 
THE SEAWEEDS 
Ballia hamulosa J. Agardh. 
Frond widely branched, ramuli and ramelli spreading in all directions, 
lower ones subspongiose, upper ones conspicuously articulate ; ramelli 
opposite or subalternate, simple or dichotomous at the base, patent, acute 
at the apices, very attenuated. Tetrasporangia on inner side of the ramelli, 
triangularly divided, firmly attached to the ramelli. Cystocarps thickly 
covering the ramelli, large, globosereniform. Colour reddish-brown. 
South Australia (Eastern Bays), Victoria. 
ANTITH AMNION Naegeli. 
Frond filiform, branched, articulated, monosiphonous, the stem and 
branches, in many species, at length thickened internally, or coated 
externally with decurrent filaments; ramuli always pellucidly articulate 
and monosiphonous. Cystocarps sessile or axillary on the branches, naked, 
containing numerous angular spores. Tetrasporangia naked, sessile or 
pedicellate, on the ramuli, triangularly divided. 
Antithamnion verticals (Harv.) J. Agardh. 
= C allithamnion verticale Harvey. 
Frond minute, creeping; larger ramuli free at ends, sparsely branched, 
opposite, densely pinnate ; pinnae regular, distichous, alternately pinnu- 
lated, parallel with rachis ; pinnellae subdistichous, furcate, dense, 
accuminate. Tetrasporangia single at the ends of the pinnellae. 
South Coast of Australia. 
Antithamnion horizontal e (Harvey) J. Agardh. 
Fronds minute, major branches at length freely branched, oppositely 
densely pinnate; pinnae almost collateral, distichous, alternate, pinnulate, 
pinnules diverging on every side, furcate, thick, acuminate; articulations 
of branches slightly shorter than broad, of pinnae equal. Tetrasporangia 
on terminal pinnules, single. 
South Australia (Eastern Bays). 
Antidhamnion (?) Hanowioides (Sond.) De Toni. 
= C allithamnion Hanowioides Sonder. 
Frond minute, creeping ; larger ramuli free at the ends, sparsely 
branched, opposite, densely pinnate ; pinnae regular, distichous, sub- 
collateral, alternately pinnulated ; pinnellae spreading in all directions over 
the ramuli, densely pinnulated, acuminate. Tetrasporangia on the lower 
pinnellae, sessile, cruciate. 
South Australia (Sturt Bay), West Australia. 
Antithamnion plunmla (Ellis) Thuret. 
Frond 10 cm. to 25 cm. long, subdistichous, widely branched at the 
articulations; ramelli opposite or verticillate, irregular, pinnulated; 
pinnellae are numerous, branched, secund, spinous. Cystocarps large, 
grouped on the upper ramelli, surrounded by pinnellae. Tetrasporangia 
elliptical or globose, large, numerous, developed on the pinnellae on the 
