418 Prof. G. J. Allman’s Biological Contributions. 
So exceedingly mutable is Corynactis viridis, perpetually ex- 
hibiting some new and strange form, according to the state of 
contraction in which it may happen to present itself, that all at- 
tempts to limit its figure in description would be vain. At one 
time it will assume the appearance of a narrow cylindrical stem 
fixed by one extremity, and bearing upon the opposite a flattened 
circular disc attached to the stem like the blade of a peltate leaf 
to its petiole. Sometimes a contraction will occur im the centre 
of the body so as to cause the animal to present somewhat the 
appearance of an hour-glass. Again, the central part of the ten- 
tacular disc will be forced forwards into an elongated conical pro- 
jection bearing the two outer circles of tentacula around the mar- 
gin of its base, and with the mouth elevated upon its apex; this 
occurs without any eversion of the stomach. In short, the strange 
shapes assumed by this protean polype are innumerable and al- ~ 
together beyond the domain of description (fig. 1). 
With the exception of the tentacula, whose structure is pecu- 
liar, the anatomy of Corynactis would appear to differ in no es- 
sential point from that of Actinia; the structure of the tentacula 
however is such as to demand here a moment’s attention. The 
tentacula of Corynactis, like those of Actinia, are tubular, and com- 
municate freely with the interseptal spaces; they are however 
imperforate at the free extremities, terminating there in little 
spherical capitula, to which the tube of the stem penetrates 
for some distance. Imbedded in the substance of these capitula 
are certain highly curious organs; they are of two kinds: one 
consists of elongated ellipsoidal or fusiform bodies which are co- 
piously scattered through the entire substance of the capitulum, 
and which appear to be formed of a filament rolled into a close 
helix and enveloped in a delicate transparent capsule (fig. 3). 
The other set of bodies contained in the capitulum are larger 
and not so numerous. ‘They are transparent elliptical ore 
with a very long filament called up within them (fig. 4). Many 
project beyond the capitulum, causing this organ to present 
under a high power of the microscope a somewhat hispid surface. 
When liberated from the tentacula in the recent zoophyte, a very 
remarkable phenomenon is presented; the capsule opening at 
one extremity gives exit to the contained filament, which uncoil- 
ing itself as it escapes is rapidly shot across the field of the mi- 
croscope (fig. 5). A spiral groove with approximated coils may 
then be traced along the entire length of the exposed filament 
fig. 6). 
: ‘On : subsequent examination of specimens which had been 
preserved for more than a year in spirits, a new feature in the 
filament of the capsule was detected. The spirits had so acted 
on it as to develope its real nature, and render manifest a much 
