supporting lamella

520 W. B. HARDY.
retracts this region to such an extent that the epithelium is
thrown into deep folds, and the free surfaces of the cells apposed.
This ciliated zone forms only a narrow band. Between
the bases of the ciliated cells are (2) numerous rounded and
deeply-staining cells, which are more numerous the nearer the
lip. Delicate processes may be sometimes seen passing from
them to the surface, and they are probably sense-cells. Below
these, and forming by far the greater portion of the epithelium,
are strikingly characteristic palisade-like cells. Each
has a very scanty and ill-stainiug protoplasm, which surrounds
a large irregular vacuole occupying the bulk of the cell. Two
nuclei, each with a small nucleolus, are usually present, and
may be either close together about the middle of the cell, or
one at either end. There is not the slightest evidence that
the presence of these twin nuclei indicates cell division.
At the lower edge of the ciliated zone conical cells appear
between and rapidly replace the ciliated cells, while at the
same time the deep-staining sense-cells disappear. Each of
these conical cells resembles in its general appearance a gobletcell
of an ordinary mucous membrane. We can, therefore,
conveniently style the next region the goblet-cell zone.
This embraces a considerable portion of the tentacle-bearing
region. It is, however, impossible to reduce the relative
dimensions of these various zones to numerical exactness
because of the extreme extensibility of this portion of the
animal.
Each goblet-cell is, as its name implies, flask-shaped, and
consists of an expanded part which stains lightly with picrocarmine
(fig. 16) or osmic acid (fig. 15). The contents
of this part are turbid from the presence of ill-defined,
granular masses. The expanded portion of the flask is
continued downwards into a tail, which contains a small
nucleus embedded in deeply-staining granular protoplasm.
The numerous and coarse granules of the basal portion stain
deeply with osmic acid, and less so with picro-carmine. These
cells are undoubtedly of the nature of gland-cells; and the wellformed
basal granules may be regarded as the first stage in