ASSUMPTION OF THE POLYPE-FORM. 358
gemmules (fig. 9) seem to escape from the walls of the
ovaries, working their way out at the sides. They
drop down on the bottom of the vessel, where they
move about slowly for a while, to no great ex-tent, by
means of their vibratile cilia.
All through September, as this species was very
numerous in the harbour and in the neighbouring
coves, I procured great numbers of them, most of
which I placed in a deep cylindrical glass vessel, —
the chimney of a lamp, in fact, with a plate of glass
cemented across one end for a bottom. By examining
this bottom-plate from beneath with a lens, I found
early in September that a good many of the gemmules
had affixed themselves to it, and were changing their
form. By watching them, I ascertained the following
facts. The gemmule, having adhered to the glass,
grows out into a lengthened form, variously knobbed
and swollen, and frequently dividing into two branches,
the whole adhering closely to the glass. After a day
or two's growth in this manner, a perpendicular stem
begins to shoot from some point of this creeping root,
and soon separates into four straight, slender, slightly
divergent tentacles, which shoot to a considerable
length. The whole is of a crimson hue, with the
exception of the growing extremities of the creeping
root, which are pellucid white. The little creature is
now a Polype of four tentacles. (See fig. 10).
I could not follow the development farther, for
though I had perhaps, a dozen in this stage, on the
bottom of the glass, they all died without farther
growth. And though, for weeks after, many gemmules