Notes on a New Boveria species. 



19 



Fig. 18. 



state, but frequently one meets with individuals possessing 2 — 6 

 meganuclei and a single micronucleus. Such polymeganuclear 

 individuals arc in percentage roughly as follows : 



Individuals with 2 meganuclei 5% ; those with 3 meganuclei 



90%" ; those with 4 meganuclei é% ; those with 6 meganuclei 1%, 



Wo see that individuals with 3 meganuclei (fig. 18, A^) are 



by far the most prevalent. As far as our observations go, the 



polynuclear condition is brought about 

 by fragmention of the single original 

 meganucleus, which process takes place 

 mostly after, and rarely before or during, 

 the conjugation. We have ascertained 

 that all the supernumerary meganuclei 

 sooner or later disappear, and only one 

 persists. From the indefiniteness of the 

 period in which the fragmentation occurs, 

 and from the persistence of the conjugant 

 meganucleus, it is evident that the present 

 case of meganuclear fragmentation is a pro- 

 cess physiologically entirely different from 

 that generally known in infusorians. 



According to our opinion, the present 

 case is to be regarded as a regulatory 

 process of the organism, which sets in 

 when the normal karyoplasmic relation tends to be disturbed in 

 Hertwig's sense, or, more precisely, when the meganuclear sub- 

 stance has made an excessive growth. In the present species, the 

 conjugant meganucleus persists and moreover fuses with three of 

 the four daughter synkarions. These facts seem, in our opinion,, 

 to provide reasons for why there must take place in the mega- 

 nucleus an occasional throwing off of the nuclear matter. 





. This figure and the next show 

 individimls ^ith suiiemumerary 

 meganuclei (3 in both). Iron 

 hœmatoxyhn. 



