'Miscellaneous. 439 



the microgonidium. Moreover, in order to avoid being projected to a 

 distance, and to keep always near the individual with which it wishes 

 to conjugate; the microgonidmm fixes itself on the auterior part of 

 the peduncle of the latter by a thin filament which it secretes from 

 its posterior part. It succeeds at length in attaching itself, by this 

 posterior part acting as a sucker, to a point of the surface of the 

 large individual, most frequently at a little distance above its inser- 

 tion on the peduncle. The microgonidium is furnished with an 

 elongated nucleus, and it possesses besides a nucleolar corpuscle 

 resembling that of the other individual. It is at the moment when 

 the cavities of the bodies of the two conjugated animalcules begin to 

 be put in communication, after the absorption of the parietal sur- 

 faces in contact, that the division of their respective nuclei into 

 smaller and smaller and more numerous fragments begins, as M. 

 Stein has described it. At the same time the nucleole in the micro- 

 gonidium is seen to enlarge and divido into two secondary nucleoli, 

 each of which is transformed into a voluminous ovoid capsule, in 

 which appear numerous filaments of extreme tenuity, arranged 

 parallel to one another. The transformations of the nucleolus and 

 the nature of its contents are identical in all points with what we 

 observe in the other Infusoria during sexual reproduction ; we must 

 therefore conclude that in the conjugation of the Yorticelliaus the 

 nucleolus plays the same part as in these latter (that is to say, 

 that of the male organ), and that the filaments developed in its in- 

 terior represent the spermatozoids of these animalcules. 



In the other individual the nucleolus does not undergo the same 

 modifications, but preserves, during the whole of the conjugation, its 

 initial rudimentary state. After all the substance of the microgo- 

 nidium has passed into the cavity of the conjoint individual, we find 

 in the interior of the latter, with the mingled fragments of the two 

 nuclei, the seminal capsules of the microgonidium, easily recognizable 

 by their striated appearance, due to the presence of the spermatic 

 filaments. The aspect which the individual presents at this moment 

 entirely recalls that of a Paramecium which has just copulated, at 

 the phase in which the nucleus is divided into numerous fragments ; 

 and in the same way also as in this latter species, some only of the 

 nuclear fragments (from five to seven) become complete ova, while 

 the rest approach one another to reconstitute the nucleus. I have 

 never seen these fragments fuse together to form a placenta, in the 

 interior of which the living embryos originate, as. M. Stein describes. 

 "We must therefore believe that, in his present observations, this 

 naturalist has again been the victim of one of those illusions which 

 led him formerly to introduce, into the genetic cycle of the Paramecia, 

 Stylonychia, and other Infusoria, creatures connected with them by 

 simple relations of parasitism, as has been shown by my old obser- 

 vations, confirmed by those of M. Metschnikoff and the quite recent 

 observations of M. Butschli. — Comptes Eendus, October 18, 1875, 

 p. 670. 



