344 M. M. Mercaur 
Mercaur (19076 and c) describes large excretory organs in 
O. intestinalis, O. caudata and O. dimidiata, and a very rudimentary 
excretory organ in O. obtrigona. No excretory organs were found in 
O. ranarum or O. zelleri, that which Detace & Herouarp interpreted 
as remnants of excretory canals in the latter species not being so. 
The excretory organ is very simple, being merely a series of enlarged 
and connected alveoles of the ordinary cytoplasmic foam. ‘The pri- 
mitive character of the excretory organs and their resemblance to 
those of Hoplitophrya is emphasized. 
LoEWENTHAL (1908) 1) found cysts of O. ranarum in young partly 
grown fanae temporariae |showing that sexual maturity of the frog 
and the approach of its breeding season is not a necessary stimulus 
and probably does not furnish any stimulus to cause encystment 
of the parasites.]| Cysts are sometimes found containing two Opalinas. 
This condition does not surely indicate division within the cyst, but 
in one observed instance arose by a fusion of at first independent 
cysts. This is regarded as very likely pathologic. N»ERrESHEIMER’s 
(1907 and 1908) description of the extrusion of chromatin spheres 
from the nuclei of encysted Opalinas is confirmed. LoEWENTHAL gives 
up his former (1904) interpretation of these bodies as micronuclei 
and accepts NERESHEIMER’s comparison of the phenomena with the 
formation of polar bodies [This I have opposed]. Stained with 
GieMsa’s solution the spheres!) are clear blue [a reaction usually 
thought to indicate achromatic nature] while the smaller granules 
are red. If the nuclei are stained with methyl green in weak acetic 
acid, only the spheres are green [a reaction generally accepted as 
almost definitive for chromatin]. Treated with acetic acid the spheres 
become more highly refractive, if ammonia be added they become 
invisible but are not dissolved, both reactions indicating that the 
spheres are chromatin [?; the nucleoli show similar reactions]. On 
the basis of the reaction to Gremsa’s stain the substance of the 
spheres is called cyanochromatin and the finer granules in the 
nucleus erythrochromatin, the two sorts of chromatin being regarded 
as functionally different, corresponding the cyanochromatin to 
SCHAUDINN’s somatic chromatin, the erythrochromatin to his sexual 
1) Through the kindness of Dr. Harrmann I have been able to read the 
manuscript of this interesting paper, sent to him for publication, and to include 
a reference to it here. 
1) Lo—wentHat cells them “Kdérperchen”. 
