ITS STRUCTURE. 255
various directions. I could not detect the least trace
of ciliary action on it, or indeed on any part of the
surface.
Within the sac, which appears to have thin walls,
there is a mass of viscera suspended from the bottom
of the furrow, and hanging down in a gradually taper-
ing cone nearly to the bottom of the interior, to which
in some specimens (not in all), the mass was tied by
a slender thread or ligament. Among the viscera
were two or three globular organs, one of which was
yellow, and appeared larger and more filled with food,
or less and more empty, in different degrees, in dif-
ferent individuals. I should have little hesitation in
pronouncing this, from its resemblance to a similar
viscus in the Polyzoa and Kotifera, to be the stomach.
The other globose viscera were colourless, but had a
turbid nucleus.
The arrangement and bulk of this mass of viscera
vary much in individuals, and in some the Avhole is
almost obsolete. In one or two there was an isolated
globose viscus far down in the cavity near the bottom.
As these specimens were smaller, I thought of the
male of Asplanchna, (a Rotiferous genus of which
these animals strongly reminded me,) in which the
digestive viscera are obsolete, and suggested the pos-
sibility of this isolated viscus being a sperm-sac. On
pressure, however, to the extent of bursting the viscus,
the extruded contents were granular, and I could not
trace any Spermatozoa. I believe that it was only
the stomach, got loose by the decay or absorption of
the connecting membranes, and floating freely in the