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 of the opening of the cell, and in the remarkable elevation of the sharp margin surrounding the upper half of the cell. In the looser aggregation, and in the form of the cells, it shows the transition from Salicornaria to Cellularia.