22 
Journal of the 
sisting of from ten to sixteen intemodes, each springing by a 
narrow base from the one below, the summit of which is continued 
upwards into a point behind it, forming, with the part between 
the divergent liydrothecse, a rhomboidal figure. Hydrotheca) 
opposite, a pair on each internode, tubular, adnate nearly to the 
aperture; those of a pair adnate or closely approximate for half 
their height in front, slightly separated behind; upper part 
divergent, ascending; aperture directed upwards and outwards, 
and a little forwards, with two prominent lateral teeth, the outer 
larger. 
Gonothecse large, pyriform or sub-globular, about five times 
as long as the intemodes of the stem; aperture operculate, 
surrounded by small irregular denticles; only one on a stem, 
springing from behind the basal part of the proximal internode. 
Colour, yellowish brown. Hab. Queenscliff. 
This species closely resembles S. minima , D'A. W. Thompson, 
(which occurs plentifully at Williamstown), but is larger, and 
differs in the hydrorhiza, which in S. minima is nearly uniform in 
width, with a series of short transverse markings along each 
margin, of which there is no trace in the present species. Both 
differ from S. pumila in having only one gonotheca on a stem, the 
position of which is constant; in the close approximation or 
adnate condition of each pair of calycles; in the cell-apertures 
being directed more upwards and furnished with longer teeth; 
and in never having more than two calycles in an internode, 
while S pumila often has four. 
S. bicornis. n . sp. Plate XII, fig. 3. 
Hydrorhiza slender, shoots pinnate, about one-fourth of an inch 
in height, stem somewhat zig-zag. Pinme alternate, each jointed 
obliquely to a process given off at right angles from the base of 
one of the long, slender internodes of the stem; each internode of 
the stem and pinna) springing by a slender base from the summit 
of the one below, which is continued upwards into a point 
behind it; internodes of the pinnae of a broad triangular form 
below the liydrothecse, slender above; the proximal one on each 
pinna short, without hydrotheca). Hydro thecae short and broad, 
opposite, one pair on each intemode, and a single one in each 
