the british - Corning Museum of Glass

xxviii INTRODUCTION.
power of the microscope, a specimen of S. nivea, while, by
touching its body rudely, I provoked it to emit its missile
filaments. Presently they burst out with force, not all at
once, but some here and there, then more, and yet more,
on the repeated contractions of the corrugating walls of the
body. Occasionally the free extremity of a filament would
appear, but more frequently the bight of a bent one, and
very often I saw two, and even three, issue from the same
cinclis. The successive contractions of the animal under
irritation, caused the acontia already protruded to lengthen
with each fresh impetus, the bights still streaming out in
long loops, till perhaps the free end would be liberated,
and it would be a loop no longer; and sometimes a new
thread would shoot from a cinclis, whence one or two long
ones were stretching already; while, as often, the newcomers
would force open new cinclides for themselves. The
suddenness and explosive force with which they burst out,
appeared to indicate a resistance which was at length
overcome:—perhaps—in part at least—due to the epithelial
film above mentioned, or to an actual epiderm, which,
though often ruptured, has ever, with the aptitude to heal
common to these lowly structures, the power of quickly
uniting again.
It appeared to me manifest, from this and other similar
observations, that no such arrangement exists as that which
I had fancied;—that a definite cinclis is assigned to a
definite acontium, or pair of acontia, and that the extremity
of the latter is guided to the former, with unerring accuracy,
by some internal mechanism, whenever the exercise
of the defensive faculty is desired. What I judge to be the
true state of the case is as follows: The acontia, fastened
by one end to the septa or their mesenteries, lie, while
at rest, irregularly coiled up along the narrow interseptal
fossæ. The outer walls of these fossæ are pierced with
the cinclides. When the animal is irritated, it immediately
contracts; the water contained in the visceral cavity finds
vent at these natural orifices, and the forcible currents carry
with them the acontia, each through that cinclis which
happens to lie nearest to it. The frequency with which
a loop is forced out shows that the issue is the result of a
merely mechanical action; which is, however, not the less
worthy of our admiration because of the simplicity of the
contrivance, nor the less manifestly the result of Divine