302 PROGRESS OF MICROSCOPICAL SCIENCE. 
of Floscularia. From this motion’s being seen so plainly in the 
nascent rotifer, I am inclined to believe that it is by this means that 
food is taken from the parent’s supply, as already suggested. The 
movements of the foetus do not seem to trouble the parent in the least 
degree, although she is, as usual, extremely sensitive to any external 
motion. The whirling of her cilia and the working of her gizzard 
are interrupted by the reproductive process only at the very instant 
of parturition. The ovarian sac opens into the cloaca, or rectum, of 
the rotifer, and the young is extruded from the anus, which is just at 
the lower edge of the upper segment of the foot-stalk or leg, and is what 
is rather indefinitely fermed, by some authors, the ‘ contractile vesicle.’ 
At the critical moment the parent draws herself violently together, 
so as to force the head of the young rotifer through the anus, and 
then the latter actively liberates itself and crawls away. At first it 
is somewhat awkward and undetermined in its movements, but, after 
creeping about for a few minutes, it attaches itself to some fixed 
object and opens out its ciliary wreaths, which it whirls as accurately 
and as gracefully as any old animalcule could do. Frequently a 
mother rotifer, containing a well-advanced embryo, also contains 
several partially developed ova, one of which may be seen to be 
' undergoing a sort of segmentation or differentiation, the gizzard 
being about the first organ to make its appearance. I have several 
times seen a large rotifer, which had been killed in some way, lying 
drawn up into a rounded mass, in which a lively young one was 
making frantic but ineffectual efforts to break through the envelop- 
ing corpse and escape. This suggests the conclusion that the de- 
velopment of the foetus, after it has reached a certain point, is 
dependent upon the parent only for food; and this supports my 
belief, already expressed, that the foetal rotifer actually and actively 
feeds, and does not merely passively imbibe. On seeing so many 
rotifers containing young as I have happened upon in the last few 
days, I am astonished that their reproductive process has not been 
oftener the subject of observation and description than it seems to 
have been. All the rotifers I now see are in the interesting con- 
dition described, and yet, according to ‘ the authorities,’ no males of 
Rotifer vulgaris have ever been discovered. Analogy, however, seems 
to indicate that this rotifer, like Hydatina, Brachionus, Melicerta, 
Floscularia, &c., is dicecious. The earlier steps in its mode of repro- 
duction are, therefore, an inviting subject for investigation. By the 
way, why do Pritchard, Carpenter, and others, persistently describe 
and draw Rotifer vulgaris with spined or hooked margins to the 
segments of the foot-stalk or leg? I think I have never seen it with 
such segments. The foot-stalk, as far as I have observed, is simply 
telescopic, like that of Acéinurus, and consists of more segments than 
are usually drawn or described—probably six. Can it be that there 
is a difference in these respects between the common rotifer of 
England and that of this country ?” 
A Tape-worm in a Cucumber (/).—It is stated that at a recent 
meeting of the Academy of Sciences, at Philadelphia, Dr. Leidy 
exhibited a specimen of a tape-worm said to havé been taken from the 
ee 
