48 
THE SEAWEEDS 
Caulerpa papillosa J. Agardh. 
Surculus glabrous, slender. Fronds erect, narrow, cylindrical, sparingly 
branched or in simple spikes, with long tapering apex, bearing minute 
imbricated globose ramenta, disposed in 16 or more vertical series. Fronds 
to 13 cm. in height. The ramenta do not collapse on drying. The slenderest 
and most compact of the three species. 
Distribution. — Victoria : Port Phillip Heads. 
Will probably be found in South Australia. 
Section Opuntioideae. 
Fronds annularly constricted, with distichous ramenta. 
Caulerpa cactoides (Turner) J. Agardh. 
Surculus stout, cylindrical, continuous (not ringed), smooth, wiin long 
rhizoids in distant clumps. Fronds erect, to 30 cm. or more high, simple or 
sparingly branched, constricted into rings and bearing large, opposite 
clavo-obovate ramenta. The rachis, naked below, bears the distichous 
ramenta above. The ramenta vesicular, to 2 cm. long, and separated by a 
constriction from the rachis. Colour a vivid green. Growing from low- 
water mark to a depth of several fathoms. 
Southern coasts of Australia. Tasmania. 
C ODIUM Stackhouse. 
A genus of extraordinarily varied external form. The thallus may 
appear as a closely adhering covering on the rock, as a spongy amorphous 
mass, as a more or less spherical ball, as an erect, cylindrical, dichotomous 
frond, as a similar more or less flattened frond, or finally as a broad flat- 
tened cloth-like segment rising erect from a narrow attachment. But, 
whatever may be the shape of the thallus, it is composed of two layers of 
which the elements are branches of one single cell. The internal, or 
inferior, layer is made up of a densely interwoven mass of colourless 
filaments, which at a localised spot, or from the whole of the lower surface 
of the frond, send down branches by which the thallus is attached to the 
substratum ; these filaments end outwards, or upwards, in green club-shaped 
terminal branches, the utricles, which are placed side by side at right angles 
to the surface of the thallus to form the outer, or upper, palisade-like 
layer. The free extremities of the utricles produce on the surface the 
appearance and feel of a soft velvet pile. 
Gametangia are borne at certain seasons laterally, usually singie, on the 
utricles. They are ovate-elongate and pointed and are of a darker green 
than that of the utricles. They are affixed at various heights on the utricle, 
are shorter than it, and do not project beyond the surface of the thallus. 
