332 M. M. Mercatr 
ParkER & Haswewu (1897) say “in Opalina numerous nuclear 
bodies are present which divide by mitosis, and therefore resemble 
micronuclei: if they are to be considered as such, this genus must 
be held to differ from the other Cilzata in the total absence of a 
meganucleus”. They refer to the processes of reproduction in the 
spring as described by Zeuer and give figures from ZELLLER, KENT 
and PritzNEeR (mitosis). 
Von ProwazEKk (1898) says that the protoplasm of O. ranarum 
stains intra vitam rosy red with neutral red, the unstained nuclei 
then being more evident. [I have not found a diffuse protoplasmic 
stain with very weak solutions of this reagent. | 
TonnicGEs (1898) recognised the alveolar structure of the proto- 
plasm of O. ranarum and distinguished the ectosare and endosare. 
He describes the cilia as perforating the pellicle [vs. Bitscun1 1887 
—1889 p. 1325. The cilia propably consist of a prolongation of 
the pellicula containing an axial fibril which extends at its base 
through the pellicula, to the basal granule. Both Birscuui’s and 
TONNIGES’ statements seem to be correct but incomplete.| and as ari- 
sing from the nodal points of a network of very delicate fibrils lying 
beneath the cuticle, ascribing the motion of the cilia to the contraction 
of these fibrils. He describes well the alveolar structure of the re- 
fractive spherules of the endoplasma. He says that they divide by 
constriction [probably an error]; that they are not excretory and 
are probably not parasitic, but are to be interpreted as a diffuse 
macronucleus. 
In a further communication the following year (1899), in regard 
to O. ranarum, he notes that the division of the body has no dis- 
cernable relation to the division of the nuclei; he describes irre- 
gular divisions of the body; he says that the several nuclei within 
the multinucleated cysts fuse into one {not confirmed by later stu- 
dents]. The nuclear membrane is described as showing alveolar 
structure [not confirmed by my study]. Amitotic division is said to 
occur side by side with mitotic division in the fullgrown forms [not 
confirmed by later students]. The true nucleolus was not observed. 
PrirzNer’s work was confirmed in that no centrosomes were found 
and the nuclear membrane was seen to persist during the mitosis. 
The chromatin is described as superficial, lying just beneath the 
nuclear membrane. No longitudinal splitting of the chromosomes 
was seen. 
BrruKkoFrF (1899) discusses VERWorn’s observations upon positive 
galvanotropism in O. ranarum. 
