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.

Fam. 2. CELLULARIADAE. Cells disposed in the same plane.

10. CELLULARIA, Pallas.

Character: (B.) Cells bi-triserial, oblong* or rhomboidal, contiguous.
Opening of cell occupying at least half of the front. Margin thickened,
sometimes spinous above. A short spine or a sessile avicularium on the
upper and outer angle.

(*Footnote. This shape of the cells is given from the back view of them.)

A. inarmatae--without avicularium.

1. C. monotrypa, n. sp.

Cells oblong, narrowed below, with a single perforation, in the upper and
outer part behind. Opening oval, margin smooth; a short spinous process
at the upper and outer angle; a sharp short spine in the middle of the
upper border of the middle cell, at a bifurcation. Ovicell ? in form of a
very shallow excavation in the upper part of the cell in front.

Habitat: Bass Strait, 45 fathoms.

The only species with which this can be confounded, is C. peachii (Busk.
Annals of Natural History volume 7 second series page 82 plate 8 figure
1.)

The latter, however, is very much smaller, the cells narrower in
proportion to their length, and the margin of the opening minutely
verrucose. The cell has more than one posterior perforation; and the
central cell at a bifurcation is rounded above and without a spinous
process; lastly, the ovicell is much loftier and tesselated on the
surface.

11. SCRUPOCELLARIA, Van Beneden.

Character (modified). Cells rhomboidal, with a sinuous depression on the
outer and posterior aspect. Each furnished with a sessile avicularium at
the upper and outer angle in front, and with a vibraculum placed in the
sinus on the outer and lower part of the cell behind. Opening oval, or
subrotund, spinous above. Ovicells galeriform.

This natural genus is characterised more particularly by the presence
upon EACH cell of a sessile avicularium seated on, or in fact forming the
upper and outer angle, and of a vibraculum placed on the back of the
cell. The cells in some species are provided with a pedunculate
operculum, by which it is intended to designate a process, which arising
by a short tube from the anterior wall of the cell, immediately beyond
the inner margin of the opening, projects forwards and bends over the
fro