
1905.| Cihated Infusoria within the Eggs of a Rotifer. 391 
these soon became condensed into cyst-walls, whilst the internal substance of 
each of them, after undergoing a series of molecular changes, resolved itself 
into an embryo Oxytricha, some of which might be seen revolving within their 
cysts. Some of this batch of Rotifers’ ‘eggs’ were seen to be filled with such 
spherical masses, whilst others were observed in which a few of the embryos 
had escaped from their cysts,and were swimming about as well-marked 
specimens of Oxytricha within the thin investing membrane of the Rotifer egg.” 
Unfortunately, nothing was stated as to the conditions to which these eggs 
had been subjected, and it was my quest in this direction, resumed about five 
years ago, that finally led to the discovery of the origin of Otostomata and of 
Vorticelle, as well as to the repetition of my observations concerning the 
heterogenetic origin of Oxytriche, from Hydatina eggs. 
Fig. 12 shows the conversion of the egg-substance into a number of large 
but unequal spherical masses; while in fig. 13 another Hydatina egg is 
shown, surrounded by Euglenz and Diatoms in a later stage of development. 
The 20 unequal spheres are exactly similar to others which were seen in 
contiguous eggs, whose development was traced into embryo Vorticelle such 
as are represented in fig. 14. 
If the egg-substance is found to have segmented into 12 to 20 more or less 
equal spherical masses, there is at hrst no means of knowing whether such 
masses are to be developed into embryo Vorticelle, or into embryo Oxytriche. 
But if either of the masses is seen to be revolving within its own delicate 
cyst, we may be sure that this particular egg will not yield Vorticelle, 
as these embryos do not revolve before rupturing their cysts, and the 
Hydatina egg produces either the one or the other form—never a mixture of 
the two. | 
It cannot be supposed that 12 to 20 of either of these Ciliates in an 
embryo condition could penetrate the egg-case, could devour its cuntents 
without being seen, and would then, as embryos, encyst themselves (all in two 
days, or less)—only, almost immediately after, again to pass out of their 
encysted condition, and to appear as the active young Vorticell, or Oxytriche, 
whose development I have traced. 
In the normal development of a Hydatina egg it never goes through 
changes in which it 1s converted into an aggregate of minute vesicles, or into 
a smaller number of separate and larger spheres, such as occurs as a prelude 
to the transformation of the egg-contents into Ciliated Infusoria of this or 
that kind. 
_ When the facts recorded in this communication are made known to other 
workers in different parts of the world, some of whom may have no difficulty 
