ah, 
284. C. CLIFFORD DOBELL. 
ment of secondary nuclei from the chromidial mass—or, as he 
then called it, “ the extra-nuclear chromatin net” of Arcella 
(text-fig. 2). And it has since been shown by Elpatiewsky 
(07) that the macro- and micro-amcebze, into whose formation 
the secondary nuclei enter, are gametes which conjugate in 
pairs.! . 
When Hertwig (’02) introduced the name “ chromidial 
net” for this extra-nuclear chromatin in Thalamophora its 
real meaning was still quite obscure. ‘he riddle was solved 
by Schaudinn (703). He found that the chromidial net (in 
Polystomella, Centropyxis, and Chlamydophrys) is 
a mass of chromatin—probably derived in the first instance 
TEXT-FIG. 2. 
Arcella vulgaris. N. primary nucleus; Oh. chromidium 
(extra-nuclear chromatin), in which the secondary nuclei (1.) 
are forming. (After R. Hertwig, ’99.) 
from the nucleus—which finally gives rise to the nuclei of 
minute gametes, which conjugate in pairs. 
Other workers have extended Schaudinn’s observations. 
In Difflugia (Ziilzer, ’04; Awerinzew, 06) the chromidia 
give origin to secondary nuclei,” which later enter into the 
' Since this paper was written the interesting work of Swarczewsky 
(08) on Arcella has appeared. In addition to confirming previous 
observations, this observer has found that a kind of conjugation ( chro- 
midiogamy ”’?) may take place between the entire chromidial masses of 
two individuals. A phenomenon to some extent parallel occurs in the 
giant disporic Bacteria, B, biitschlii (Schaudinn, ’02) and B. flexilis 
(Dobell, ’08a). 
* And also form glycogen (Ziilzer). 
' 
