.

Habitat: Bass Strait, 45 fathoms. Off Cumberland Islands, 27 fathoms,
fine grey mud.

Parasitic upon Sertularians and Polyzoa; branches straggling of irregular
lengths.

2. S. bicornis, n. sp.

Areas with an obtuse angle above and below, sometimes rounded above; a
minute projection on each side near the top. Bottom of area long-oval,
smooth, sometimes with a perforation above the mouth. Mouth with a minute
tooth on each side.

Habitat: Bass Strait, 45 fathoms.

Parasitic. Branches shorter and thicker than in the preceding species. In
the shape of the area they are very much alike, but in S. bicornis, in
some cells, and occasionally throughout the greater part of the
internode, the area differs widely from the more usual form. It is much
expanded, and presents a wide arch above. In this case there is usually a
considerable-sized perforation above the mouth of the cell, as occurs not
infrequently also in S. farciminoides in the younger cells, and which
opening is probably normal, until it becomes filled up by the gradual
disposition of calcareous matter. What more especially distinguishes the
present from the preceding species are the minute projections on either
side at the two upper lateral angles of the hexagonal area, and the
smoothness of the surface of the cell. They are both perfectly distinct
from S. farciminoides.

b. Surface not divided into distinct areas by raised ridges.

3. S. furcata, n. sp.

Mouth of cell elliptical, occupying two-thirds of its length. Two small
perforations on each side immediately above the mouth, protected by a
convex transparent hood, which has a rounded opening on its under
surface.

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

Forms small crowded tufts from one to two or three inches high; branches
very regularly dichotomous.

4. S. torresiana, n. sp.

Cell circumscribed by an acute raised border; opening oval, rather more
than half the length of the cell. Cell attenuated below the opening.

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

A small broken fragment only preserved; parasitic upon Sertularia
mutulata, so that its habit cannot be satisfactorily determined. It is of
a greenish colour, but this may be adventitious, although general and
uniform throughout the specimen. This species differs from the above in
being much larger, and in wanting the two perforations on each side above
the mouth--in the less comparative size