les about half an inch; thickly and
regularly disposed, alternate.

3. P. delicatula, n. sp.

Cell cup-shaped, rounded, mouth at an angle of 45 degrees; margin
dentate, with two lateral teeth of equal size and a central one in front
longer, all acute; entire posteriorly. Rostrum a little longer than the
cell, scarcely connected with the rachis, slender, and closely adpressed
and adnate to the cell below, wide and projecting upwards; lateral
processes large, rising above the margin of the cell, conical, tubular,
or canalicular.

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

Colour of rachis and pinnules, delicate yellowish white above; of rachis,
light brown, inferiorly; polypidom about two inches high, rising in
several straight simply pinnulated fronds from a common centre; pinnules
ascending about 1/4 inch.

4. P. aurita, n. sp.

Cells cup-shaped, tapering at bottom, constricted just below the top;
mouth at an angle of 45 degrees, circular; margin subcrenate, plicate,
with three folds on each side, with a wide shallow notch in front and
entire behind. Rostrum, slender, attenuated below, adnate up to the cell,
summit contracted, tubular; lateral processes very long, expanding,
rising far above the margin of the cell, conical, tubular.

Habitat: Off Cumberland Isles, 27 fathoms.

Colour bright brown; polypidom 2 to 3 inches high, consisting of straight
pinnate fronds, pinnae or branches not opposite, nor regularly alternate,
divaricate at rightangles.

5. P. brevirostris, n. sp.

Cell sub-tubular, curved; mouth expanded with two equal acute teeth on
each side, and a longer narrow and slightly incurved, central one in
front. Rostrum small, conical, projecting, about half the length of the
cell; lateral processes small, recurved at an angle, canalicular.

Habitat: Off Cumberland Isles, 27 fathoms.

Colour dirty white. In habit, and to the naked eye, very much like the
last; its growth, however, appears to be longer and less regular. The
difference in the cell is very great.

6. P. ramosa, n. sp.

Cells cup-shaped, deep, rounded at bottom; margin elevated on the sides,
expanding, with four teeth on each side, the first and second in front
much expanded, acute, incurved at the point; a long slender incurved
central tooth in front; margin entire behind. Rostrum not continued to
the rachis, adnate the whole length of the cell, wide and projecting,
narrowed to the point, which is tubular, op