which arises a single branch. The
cells on the stem are alternate.

b. Cells secund.

11. S. trigonostoma, n. sp.

Cells ovoid, gibbous, much contracted towards the mouth. Very small
portion free, projecting forwards and outwards. Mouth looking outwards
and forwards, triangular, with a short blunt tooth on the external angle.
Ovicell ---- ?

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

Colour very light yellowish. Polypidom simply pinnate, about two inches
high: longest pinnae about half an inch. Cells small adnate, projecting
suddenly at top, and much contracted at the mouth. The mouth is of a
triangular form, the longest side of the triangle being below. The cells
are placed in pairs, but one is always a little higher than the other
(subalternate) and one pair is placed on each internode on the pinnae.
The stem is also indistinctly divided into internodes, from each of which
a single pinna is given off alternately on opposite sides, and besides
the pinnae there are three cells on each internode, two on the side from
which the pinna springs, and on the opposite side alternate in position
to the other two.

12. S. digitalis, n. sp.

Cells digitiform, slightly curved to the front, mouth circular, looking
directly upwards. Margin entire, expanded. Ovicells long-ovoid, muricate,
spines numerous crowded, mouth prolonged, tubular.

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

Colour dark grey, almost black. Stem two or three inches high, rising
either from a strong main trunk (?) or from a mass of intertwined radical
tubes. Stems or branches pinnate: pinnae or branches alternate, straight,
divaricate. The cells forming a pair, are, on the branches, adnate to
each other throughout their whole length. But on the stem the cells are
distichous and wide apart. The ovicells are peculiar in their long
flask-like form, and tubular mouth. They are placed all on one side of
the rachis, generally in single file, but sometimes in pairs.

13. S. loculosa, n. sp.

D. distans ? Lamouroux.

Cells completely adnate to each other, each apparently divided into two
compartments by a transverse constriction. Upper half turned horizontally
outwards. Mouth roundish, irregular, contracted: looking outwards, and a
little downwards. Ovicell ---- ?

Habitat: Bass Strait, 45 fathoms.

Colour deep brown; polypidom simple unbranched (?) about half an inch
high, parasitic upon a broad-leaved fucus. The cell