een dried, without a movable
mandible, and are probably really so, because there is no corresponding
beak. These processes are channelled in front, nearly from the base to
the extremity; they arise by a broad base on each side of the mouth, and
on the front of the cell, and from the conjoined bases is continued
upwards and downwards, or to the top and bottom of the cell, a prominent
flattened band. The expanded bases circumscribe an oval space, nearly in
the centre of the front of the cell, the upper two-thirds of which space
are occupied by the circular mouth, on each side of which is a small
calcareous tooth, to which apparently are articulated the horns of the
semilunar lateral cartilage. The lower third is filled up by a yellow,
horny (?) membrane, upon which are placed three conical eminences,
disposed in a triangular manner. The back of the cell is very convex, and
has running along the middle of it an elevated crest or keel, which is
acuminate in the middle. The ovicell is situated in front of the cell
below the mouth, and below it are three considerable-sized areolated
spots, disposed, like the three conical spines, in a triangle. The cells
upon which the ovicells are placed are always geminate, that is to say,
have a smaller cell growing out from one side.

6. Calpidium, n. gen. Table 1 figures 3 to 5.

Character: Cells with an avicularium on each side; with two or three
distinct mouths, arising one from the upper part of another, in a linear
series, all facing the same way, and forming dichotomously-divided
branches; cells at the bifurcation single; ovicells ---- ?

This very peculiar genus, remarkable as it is, seems hitherto to have
escaped notice. It is distinguishable from Catenicella, in the first
place, by the anomalous circumstance that each cell is furnished with two
or more, usually three, distinct keyhole-shaped mouths, and is doubtless
inhabited by three distinct individuals. Whether these are separated from
each other by internal partitions is unknown, but the closest examination
of cells rendered transparent by means of acid fails to discover such. In
cells thus prepared, there are apparent, however, three distinct masses,
reaching from the bottom of the cell to each orifice, and which are
probably the remains either of the body or of the retractor muscles of
the animals. Another point of difference from Catenicella is the
non-gemination of the cell at the dichotomy of a branch. The avicularia,