536 
nying series of figures of mitotic phenomena (figs. 14 to 21) are from 
the nuclei of one of two multinucleate species of Opalina abundant in 
the large toad of California, Bufo halophilus. This Opalina seems to be 
an undescribed species somewhat intermediate between O. ranarum and. 
O. obtrigona. I do not here describe and name it, reserving this until 
I publish a more general systematic study of the Opalinas. In my notes 
I am calling it O. intermedia, and for convenience will so refer to it here, 
but the name may not stand. 
In the resting condition the nuclei of this species resemble those 
ot O. ranarum, O. obtrigona, O. dimidiata, O. flava and other as yet 
a 
Fig. 10. An individual of Opalina antilliensis, showing some of the axial vacuoles of 
the excretory system, also the slight posterior protuberance, and a trailing mass of 
excreta. X 280 diameters. 
Fig. 11. An individual of O. antilliensis, showing excretory vacuoles. X 280 dia- 
meters. 
undescribed multinucleate species I have studied. There is a network 
of chromatin beneath the nuclear membrane, the nodes of the network 
being enlarged into irregular masses of unequal size. In addition there 
are large clumps of chromatin clinging to the inside of the nuclear mem- 
brane. As mitosis approaches, the chromatin network resolves itself into 
lines of granules which appear later, in the spindle stage, as linear gra- 
nular chromosomes resembling those of the granular type in O. antil- 
liensis, as described above, and they separate to the daughter nuclei in 
the same way. The coarse chromatin masses on the other hand, do not 
form chromosomes at all. There are no massive chromosomes in the 
multinucleate Opalinas. Upon the spindle, along with the linear gra- 
nular chromosomes, one finds from one to four or five irregular masses 
of chromatin, which do not divide during the mitosis, but are carried 
