M. A. Schneider on Ophryocystis Blitschlii. 307 



21) taken separately. I shall only remark that I recognize 

 the nucleolus only with some trouble in these nuclei and in 

 those which will now be mentioned. 



What becomes of the two nuclei of the cyst? It seems to 

 me impossible to doubt the fact of their division. Each of 

 them divides first of all into two, as shown by figs. 22 and 

 26. This I say is certain so far as we can arrive at certainty 

 in comparative investigations, for the volume of the four new 

 nuclei is so considerably inferior to that of the two original 

 ones that the difference immediately strikes the observer. 

 Then two of these nuclei divide again, and we get the number 

 six, three nuclei in each half of the cyst, in the periphery 

 of each individual. For, it must be remarked, up to 

 this time the conjugation, which appears complete so long as 

 we regard only the surface, has not yet had any profound 

 effect. It is more than probable that the two plasmatic 

 masses have not become confounded, and it is certain that the 

 nuclei have continued the property of their original bearers. 



Arrived at this point we may stop a moment to run over 

 our recollections. I shall soon prove that in the Gregarinse 

 also, and in all of them, the deeper mingling of the encysted 

 masses is late and is preceded by a special nuclear evolution. 

 This would be a further point of analogy with the Gregarinaj. 

 But if we consider purely and simply the cysts with six 

 nuclei (figs. 19 and 23), may we not fancy we are looking 

 again at one of Biitschli's figures ^ ? In fact, since the 

 publication of that naturalist, we know that the Myxospo- 

 ridia engender bodies with six nuclei in their plasma, each of 

 which becomes the mother-cell of two spores. Now the origin 

 of the six nuclei appears very clear in Opliryocystis. They 

 are derived from two nuclei belonging to distinct terms, 

 nuclei which have proliferated under the influence of a conju- 

 gation. Should not this observation lead to a fresh scrutiny 

 of the origin of the mother-cells of the spores in the Myxo- 

 sporidia ? 



The sequel of oui investigation will show us two curious 

 facts, establishing a profound difference from the Myxospo- 

 ridia. Thus, on the one hand, all the plasma of the cyst is 

 not employed in the formation of the reproductive element, 

 which reminds one of the Gregarinse ; and, on the other, four 

 nuclei out of six are abandoned, a peculiarity which appears to 

 me to be unique, and which is one of the most characteristic 

 features of this curious form. When I found Oijliryocystis 

 I thought for a moment that 1 had oae of those pure and 



* O. Biitschli, he. cit. pi. xxxi. fig. 36, and ' Protozoa,' pi. xxxviii. 

 fic/. \\h. 



