up-like cavity above; second, a middle
compartment, the avicularium; and third, a third loculament below the
avicularium, the wide opening of which is covered in by a convex
transparent membrane. The bottom of this loculament appears to be
perforated, and it is to be noticed also that there is a small central
perforation in the septum separating it from the cavity of the
avicularium. Towards the bottom of the cell, on each side, is a well
developed lateral area of exactly the same conformation as the
sub-avicularian loculament, and like it covered in by a convex
transparent membrane. It might be supposed that these cavities were for
the purpose of containing air, in order to render the otherwise heavy
branches of the polyzoary buoyant. They, at all events, appear to be
perfectly empty.

7. C. cribaria, n. sp.

Cells sub-globular, compressed, more or less alate. Avicularia large,
without any superior appendage, and prolonged downwards into elevated
lateral alae. Anterior surface with numerous small round fenestrae,
placed at equal distances apart, and evenly distributed over the surface,
the circumferential fenestrae being larger than the rest. A minute
central perforation of a crescentic form, the lower lip projecting, and
the upper lip, lingulate in the middle, falling behind the lower.

Habitat: Bass Strait? This species also occurs in New Zealand.

Colour brown, loosely branched and several inches high. Distinguished
readily by the cribriform aspect of the front of the cell, and by the
curiously formed central orifice, and by the absence of any superior
appendage to the avicularium.

b. Vittatae.

Cells furnished with a narrow elongated band or vitta on each side,
without fenestrae. Ovicells not terminal, galeriform.

8. C. formosa, n. sp.

Cells oval; avicularia large, flat, or cupped above. Vittae elliptical,
rather anterior.

Habitat: Swan Island, Banks Strait.

Colour light plumbeous. Parasitic upon C. margaritacea. The cells are the
largest of any in the Vittate division, and very regular and uniform in
size and outline. The more distinctive characters are taken from the
comparatively broad vittae, and the flat or cupped upper surface of the
avicularia, which are usually continued downwards into a prominent ridge
or ala.

9. C. gibbosa, n. sp.

Cells pyriform, ventricose posteriorly, much attenuated at bottom.
Avicularia small, placed in front close to the sides of the mouth, at the
base of stro