in the position of
the avicularium when the latter organ is present. The lower half of what
would otherwise be the oral opening of the cell is filled up by a thin
plate of calcareous matter, granulated on the surface, and by which the
actual opening is rendered more or less subtriangular, the mouth being
placed just below the apex of the triangle. The margin of the opening is
considerably raised, especially at the oval end, so that the opening
appears to be situated in a deep depression. This character of opening,
however, occurs also in a triserial species of Cellularia from Algoa Bay.
The position of the avicularium entirely BELOW the level of the opening
on the outer side of the cell, is the peculiar characteristic of Emma as
distinguished from Tricellaria, in which that organ when present is
placed on the upper and outer angle as in Cellularia proper, and
Scrupocellaria. It is worthy of notice that avicularia may be present on
every cell in some specimens, and most usually, whilst in others of equal
size there will be none at all apparent. So that the position of these
organs in this genus, as well as in Tricellaria, is of more importance
systematically than even their existence.

1. E. crystallina, Gray, l.c.

Cells in pairs; three spines on the outer edge, the central usually the
longest and strongest.

Habitat: Bass Strait, 45 fathoms.

Parasitic upon Polyzoa, etc. circinate branched--branches irregular
divaricate. The opening of the cell triangular, very obliquely placed.

2. Emma tricellata, n. sp.

Cells in triplets; three or four long spines on the upper and outer part;
a small spine on the inner and lower part of the edge of the opening.

Habitat: Bass Strait.

Parasitic upon Catenicella, etc. Habit long straggling, very like the
preceding species. The cells are more infundibuliform, and the
avicularium, which, as in E. crystallina is not always present, is
larger, but occupies the same position on the cell.

2. Polyzoary continuous throughout.

Fam. 3. BICELLARIADAE. Frond wholly divided into narrow ligulate,
dichotomous, bi or multiserial branches; no vibracula. Avicularia when
present pedunculate.

14. BICELLARIA, Blainville.

Character. (B.) Cells turbinate, distant. Opening directed more or less
upwards. Mouth submarginal. Several curved spines, marginal or
submarginal.

1. B. tuba, n. sp.

Opening round, looking nearly directly upwards; a digitiform hollow
process below the outer