300 M. M. Mercaur 
318—321, Pl. XXVIII). This fact renders the species unfavorable 
for the study of the nuclear phenomena following copulation. 
NERESHEIMER’s Text Fig. B. (page 26) is very interesting. That 
which he interprets as budding was probably copulation. The second 
figure seems to indicate the copulation of three microgametes with 
one macrogamete (my Text Fig. XI, Page 294). I have often seen 
two males attached to one female, but in every case the attachment 
was a loose one and not true copulation (cf. O. caudata, Fig. 271, 
Pl. XXVIJ). In the instance figured by NerEsHErmeER the union 
seems to be an intimate one indicating true conjugation. It is to 
be regretted that NreresHErmerR does not figure the nuclei. If the 
macrogamete had several nuclei there seems no reason why several 
male nuclei might not enter at the same time and fuse with them. 
Opalina ranarum. 
I have not seen the gametes of O. ranarwm. I have found 
the multinucleated cysts as described by other students (Fig. 326, 
Pl. XXVIII). The zygotes show large spindle-shaped nuclei, re- 
sembling those of O. dimidiata, O. intestinalis and O. caudata (Fig. 827, 
Pl. XXVIID. 
Further general considerations. 
Vegetative chromidia. 
The extrusion into the cytoplasm of a portion of the chromatin, 
preceeding sexual reproduction, seems in all probability to be a 
throwing off of vegetative chromatin’) comparable to that described 
by R. Herrwic, Scuauprnn and others in so many Plasmodroma. 
The disappearance of the macronucleus in conjugating Ciliata is prop- 
ably a similar phenomonen. The solution, and osmotic expulsion 
from the nucleus, of the chromatin spherules during each mitosis in 
the asexual generation is probably also a somewhat related phe- 
nomenon, the chromatin spherules being probably nutritive, and their 
extrusion into the cytoplasm probably having to do with nutrition, 
") It seems to me altogether probable that there is no fundamental distinction 
between generative and vegetative chromatin, the latter being derived from the 
former. Generative chromatin is probably complete perfect slightly specialized 
chromatin, vegetative chromatin being secondary modified chromatin. If the 
modification is too great the vegetative chromatin is unable to share in the pro- 
cesses of conjugation and so degenerates. (Compare Herrwia 1907.) 
