M. A. Schneider oti Opliryocystis BUtselilii. 309 



is already individualized, although still far from its definitive 

 size. It is spherical in this stage, placed in the plane of the 

 equator, and fitted in between two spherical hoods, which it 

 already lifts sufficiently to cause a tolerably wide space to exist 

 between them in the equatorial zone. Fig. 29 shows a more 

 advanced stage, also from the life. The spore has increased 

 in size 5 it has attained its definitive dimensions ; it has its 

 double wall ; the two hoods which just now existed, puslied 

 more and more towards the poles, have become obliterated. 

 In place of the considerable number of granules that they 

 had in the former specimen, they have only a very small 

 number, and appear as if exhausted. Fig. 33, however, 

 represents them as still well marked ; but when we come to 

 fig. 34, and especially to fig. 31, we find them still more 

 reduced, and even broken up into granules, which float 

 disseminated in the liquid that has appeared to replace them 

 in the interior of the cyst. 



While these appearances were showing themselves exter- 

 nally, what has taken place within the cyst ? Of this we 

 can form an idea only by comparing preparations rendered 

 transparent. 



We have seen that six nuclei existed in the cyst. Two of 

 these nuclei placing themselves in the equatorial plane, and, 

 according to my interpretation, fusing together and consum- 

 mating the conjugation, which up to that time remained 

 incomplete, are going to constitute the spore. The other 

 four, continuing in their respective hemispheres, will remain 

 immersed in the granular hoods, the destruction of which 

 they will share. Thus figure 15 expresses, in my opinion, 

 the commencement of the phenomenon, and it corresponds to 

 figure 41, which we have just been considering ; while fig. 17, 

 corresponding to fig. 29 from the life, shows the perfect com- 

 pletion of the sporoblast. 



The sole point upon which I may be mistaken relates to 

 the fusion of the two nuclei of the spore into a single one. 

 This is why, strictly speaking, an error may be possible. If 

 fig. 15, instead of presenting the ideal axis which unites its 

 two nuclei in the plane of the preparation, showed it oriented 

 perpendictdarly, the two nuclei being projected more or 

 less one over the other would represent a single spherical or 

 oval body, and it would no doubt be difficult in such a medium 

 as balsam to distinguish the superposition. Thus I cannot 

 venture to assert that, by having foreseen them, I have avoided 

 all causes of error. There is indeed one argument, namely 

 the diameter of the single nucleus. But if the superposi- 

 tion of the two nuclei be incomplete, the diameter of their 



