back part of another, with the
intervention of a short corneous tube which is prolonged from the
interior of one cell to that of the one above. The cell is furnished on
each side at the top with a usually well-developed avicularium, in some
species of huge size, and in some very minute, or entirely aborted. This
avicularian process in most cases supports above a hollow process, which
is sometimes closed and more or less elongated, constituting a conical or
acerose spine, sometimes open above and assuming the form of a shallow
cup or receptacle. In some species both modifications of this portion of
the lateral process are met with in the same specimen. This form of spine
or cup--as the case may be, is always distinctly separated by a septum
from the cavity of the avicularium itself. Below the avicularium there is
also in many cases a third distinct cavity which is usually widely open,
the opening being covered in very frequently by a convex transparent
membrane, and its bottom apparently perforated by several minute
foramina--from this part of the lateral process there is in many species
a prominent ala or keel prolonged to the bottom of the cell--which ala
not unfrequently divides into two branches, which, again coalescing at
the bottom of the cell, circumscribe a more or less oval space, the
bottom of which is also perforated by minute foramina or apparent
foramina, and which is often covered over by a transparent convex
membrane. This membrane, however, as well as that which covers in the
subavicularian space, is more usually broken off and wanting.

The inferior oval space above described is here termed the lateral area,
and it is employed in the specific characters. It would thus be correct
to say--that each cell is furnished with two lateral processes, each of
which in the fully developed state consists of three distinct
compartments--one superior, a cup or spine: a middle one, which is the
avicularium: and an inferior; and it would appear that one or more of
these elementary compartments of the lateral process may be more
developed than the next, or sometimes entirely aborted. The mouth of the
cell is situated at the upper part in front, and is of the same
conformation as in the rest of the Cheilostomatous suborder. An important
generic character consists in the gemination of the cell at each
bifurcation.*

(*Footnote. Table 1 figures 1 and 2.)

These characters are common to all the species included in the gen