File:A naturalist's rambles on the Devonshire coast (Page 297) (5981276566).jpg

ITS STRUCTURE. 297
The genus is distinguished from Laomedea by the
cells being placed on long ringed footstalks, wliich
spring in an irregular crowded manner from a
creeping adherent stem. The stem in this instance
had twined about the slender fronds of a small
sea-weed.
The cells in this species are shaped like an old-
fashioned ale-glass, being long and narrow, with a
slight constriction just above the point of their con-
nexion with the footstalk ; and at this constriction, a
sort of false bottom, or diaphragm, runs across, which
is perforated with a narrow hole in the centre. (See
Plate XVIII, fig. 1). The margin is cut into about
eleven deep equal teeth, and expands in a very slight
degree (fig. 2). The stalk has usually about six or
eight well marked rings at each extremity, the middle
portion being smooth. The walls, both of the stalk
and cell, are thin, and perfectly transparent and colour-
less ; the former is permeated, but not filled, with the
medullary core, through which a fluid circulates,
carrying minute granules with a quivering jerking mo-
tion. This core is exceedingly attenuated to pass
through the perforated diaphragm of the cell, after
which it merges into the body of the polype.
The polype (fig. 1.) is slender (when protruded);
dilated at the base into a sort of foot which spreads
over the diaphragm, and widening still more at the
top, where it fills the mouth of the cell, and gives
origin to about twenty (less or more) slender tenta-
cles, rougheoed with whorls of tubercles, and set in
two or three series. In the central space surrounded