25 
On Vaginicola valvata. 
By C. J. Muller, Esq. 
With Plate VII. 
In October last I found attached to filaments of a Conferva, 
occurring in the brackish water of a ditch draining the marsh- 
land at Eastbourne, numerous specimens of Vaginicola 
valvata (PI. VII, fig. 1). Having kept them under daily obser- 
vation for some time, I am enabled to furnish a few particulars 
of the life-history of these curious animalcules. 
If a case containing a single specimen be kept sufficiently 
long under microscopic observation, the following phenomena 
will probably be witnessed. The creature, having retreated 
into its cell and remained for a time quiescent, with its 
cilia withdrawn and apparently obliterated (fig. 2), there 
ultimately appears at the base, just above the stalk by which 
it is attached to the cell, a conical fissure (fig. 3). Very 
soon after this has made its appearance, a wavy line of divi- 
sion shows itself at the upper extremity of the animalcule 
(fig. 4). These fissures gradually enlarge and elongate, the 
lower one becomes forked in appearance (fig. 5), and the two 
lines approximate until they meet (fig. 6). Pulsating 
vesicles are active on both sides of the line of fission, and in 
each division, at a spot marked a in fig. 6, a languid move- 
ment of internal cilia may be observed. The animalcule now 
extends itself somewhat, but without protruding from the 
cell ; all at once it contracts itself with a jerk, and then there 
expand, by slow degrees, two distinct animals (fig. 7), the one 
being longer than the other. This action of fission occupies 
about one hour. 
As yet, however, the upper portions of both creatures are 
unformed and incomplete ; they are mere rounded extremi- 
ties, with an obscure internal languid movement of cilia. 
They elongate somewhat, and, after a time, acquire a curious 
contorted appearance (fig. 8). While in this state the 
upper extremity of each begins to assume a disc-like form, 
the cilia increase in size and activity of movement, and, by 
degrees, a greater and greater portion of the tube becomes 
occupied; a dense, transparent fluid appears at the upper 
extremity, and is seen to oscillate backward and forward, 
under the influence of the cilia, somewhat in the manner of 
the balance wheel of a watch, but with a slow, steady motion. 
The cilia appear to be engaged in this w r ay in shaping and 
constructing the upper extremity. After a time the two 
