388 Prof. H. C. Bastian. On the Occurrence of certain [Feb. 14, 
previously seen, great Ciliates may be found slowly revolving within the 
egg-case, as with the specimen shown in fig. 6 before it was killed by a weak 
iodine solution ; or else, under the influence of the light, rupturing the egg- 
case, struggling out, as in fig. 7, and swimming away with rapid movements, 
partly of rotation. Some of the Infusoria before they emerge undergo 
segmentation into two, four, or rarely, even into eight smaller Ciliates. An 
undivided specimen which had been swimming about for half an hour, and 
in which the cilia are better developed, is shown in fig. 8. 
The large undivided Infusoria have their bodies densely packed with large 
corpuscles (modified representatives of the vesicles of an earlier stage); and a 
large elongated nucleus which can be seen in some of them, though generally 
not well without the aid of reagents. They possess the characteristic ear- 
shaped mouth indicated by the name Otostoma, and cilia are distributed all 
over the body in longitudinal lines, so as to give the appearance of a delicate 
longitudinal striation—both these features being visible in the starved 
specimen represented in fig. 9. 
In the event of the Ciliates being not yet fully developed at the time that the 
second pot is opened, we have the third pot, whose contents we can investigate 
slightly later. 
As a control experiment it will be well at the time that the pots are charged 
to place two or three batches of the eggs with some of the same water into a 
watch glass, which is left exposed to light; and at the expiration of three or 
four days, as well as at later periods, to search among its contents for any of 
the same large Ciliates, and also for any eggs in the intermediate vesicular 
stage above referred to. I have invariably found that such a search yielded 
only negative results. 
In taking batches of eggs, in the manner indicated, to be placed in the 
pots, individual eggs will necessarily be of different ages. Some will have 
already begun to develop into Rotifers, and some of these, under the altogether 
unnatural conditions to which they are subjected in the dark pots, are apt to 
become more or less malformed as development proceeds. Others that have 
been quite recently laid will not have begun to develop, and it is these latter 
eggs apparently, which, under the cutting off not only of ordinary light but 
probably of some invisible light rays, become speedily transformed into great 
Ciliated Infusoria. Cutting off ordinary light rays alone from the eggs, by 
placing them in a small covered glass dish shut up in a cupboard or box and 
maintained at the same temperature as before, seemed at first not to lead to 
similar results; but I subsequently ascertained that the transformation will 
occur under such conditions, though only after the lapse of about nine 
days. It looks, therefore, as if the stoppage of some invisible rays, 
