OF CILIATED INFUSORIA 279 



represented in Fig. 74, B ( x 250) only by a heap of fine granules, 

 just above the small x marked thereon. The lighter of the three 

 spheres, which did not stain so deeply with iodine as the other 

 two, is the one that contained the revolving embryo. Another 

 sphere, with motionless contents, was situated in a deeper plane, 

 and is not shown in the photograph. Close by the side of this 

 ruptured egg there was another containing two similar spheres, 

 and further away I found a third ruptured egg-case containing a 

 single sphere of the same size and appearance, each of them having 

 motionless contents.' I had also previously found some remarkably 

 altered eggs which I thought might prove early stages of this kind 

 of transformation ; and others of a similar nature have since been 

 found in which, instead of the occurrence of a multitude of minute 

 vesicles, all cohering together, such as occurs when the egg is 

 being transformed into an Otostoma, the egg-substance seems to 

 divide into, or to give origin to, a much smaller number of larger but 

 separate units (such as are to be seen in Fig. 76), which may have 

 the power of developing independently. In Fig. 77, A (x 250) 

 other unequal spheres, of intermediate size, are to be seen which 

 consequently might yield different products.'' 



The summer being unusually dry, it was not till after rain had 

 fallen for some days that I at last succeeded, on September 22nd, 

 in getting another supply of Euglenae together with Hydatinje. 

 After placing them in water, they were left undisturbed for a few 

 days in order to obtain a good supply of eggs. Portions of the 

 pellicle were then transferred exactly as before to small covered 

 pots almost full of water, and they were then kept at a temperature 

 of about 66° F. (19° C). Examination of a portion of the pellicle 



' I have found that in cases where transformation of the egg-substance into 

 an Otostoma has taken place, and the organism has subsequently undergone 

 segmentation into four, that one of the segments has occasionally lagged behind 

 in a motionless state, after the others have disappeared. So that, with multiple 

 partition of the egg-mass, such as occurs when Oxytrichae are produced, it is easy 

 to understand that all segments may not develop exactly at the same time — 

 hence the occurrence of remainders, such as I have just referred to, would be 

 explicable. 



' In connection with this point it is worth mentioning that on two occasions 

 I have taken from one of my pots partly empty Hydatina egg-cases, each of which 

 contained 15-20 young, active specimens of the very small Ciliate known as 

 Aspidisca costata. Yet in all the other examinations that I made during the same 

 month, and they were numerous, I only met with the specimens of Aspidisca 

 that were within these two eggs, and a few others, at the same time, 

 in their immediate neighbourhood. 



