ve
to be a variety. The cells, however, throughout the whole of the
polypidom are of precisely the same character, in each form, and exhibit
no intermediate steps. In the present species the cells are much longer,
rather narrower, and the upper half is turned out abruptly at a
rightangle, whilst in the former they ascend at an angle of 45 degrees,
and the free portion is much shorter. The branches in both are opposite;
the ovicells are unfortunately absent in each.

8. S. mutulata, n. sp.

Cells compressed or flattened, from side to side; sometimes angular,
lower half adnate, upper half divergent, projecting like a bracket. Mouth
looking directly upwards, narrow oblong, quadrangular. Ovicells aculeate,
with strong widely set spines, pyriform depressed.

Habitat: Prince of Wales Channel, Torres Strait, 9 fathoms.

Colour light olive grey. Polypidom about three inches high, irregularly ?
branched, branches not opposite. The cells are distichous, and of a very
peculiar form, but varying in some degree according to their situation.
The younger (?) cells on the secondary branches are flat on the inferior
or outer aspect, with two angles on each side, or are quadrangular;
whilst the cells on the stems or older or fertile branches are usually
rounded below, or on the outer side, and thus have only one angle on each
side. The mouth varies in shape according to the cell; in the former case
being a regular long rectangle, whilst in the latter it is rounded on the
outer side. The ovicells are placed in a single series on one side of the
rachis, as in S. digitalis, but are widely different in form.

9. S. operculata, Linn.

Habitat: Swan Island, Banks Strait.

This species occurs in all parts of the world. It is to be carefully
distinguished from S. bispinosa, Gray--also an Australian and New Zealand
species, but which does not occur in the present collection.

b. Cells (on the branches) secund, contiguous.

10. S. divergens, Lamouroux.

Cells urceolate, much contracted towards the mouth; upper half free,
divergent, projecting laterally almost horizontally; mouth small
elliptical, with the long axis looking directly outwards; two lateral
teeth. Ovicell smooth, rounded, ovoid; oral margin not elevated.

Habitat: Swan Island, Banks Strait.

Colour light yellowish: parasitic upon a fucus. Height from 1/4 to 1/2
inch; simply pinnate, branches distant, regularly alternate. The stem is
divided into internodes, from each of