CHROMIDIA AND THE BINUCLEARITY HYPOTHESES. 285 
composition of gametes. A similar condition appears to 
prevail in Kuglypha, Trinema, Hyalosphenia, Nebela, 
etc. (Awerinzew, 706). 
Schaudinn’s observations on Polystomella have been 
largely confirmed also in the case of Peneroplis (Winter, 
07). Lister (06) has already given a brief review of the 
nuclear phenomena in the Foraminifera. 
Recently Doflein (?07) has re-examined many Thalamo- 
phora—namely, Arcella (2 species), Platoum, Euglypha 
(2 sp.), Trinema, Gromiella, Lecquereusia, Nebela,(2 
sp.), Difflugia (5 sp.), Pseudodifflugia, Centropyxis, 
Cochliopodium. A chromidial net was. found in all, 
though its nuclear origin was not clearly made out. Its form 
shows great variation, being sometimes compact, sometimes 
diffuse. And it also varies considerably as regards the 
relative quantities of plastin and chromatin present in it. 
On the whole it seems that the chromidial net of the Thala- 
mophora is a structure of nuclear origin whose chief purpose 
is to supply gamete nuclei. 
(5) Amcebina.—Amongst the amcoebe three forms have 
received special attention—Hntamceba coli, Peloxyma, 
Amoeba proteus. 
In the first, Entamoeba coli Loesch, Schaudinn (’03) 
found that an autogamy takes place, in which chromidia play 
apart. Two daughter-nuclei in an encysted animal break up 
into chromidia, which are subsequently, in part, eliminated. 
The remaining chromidia mass themselves together to form 
two new nuclei, which, after each giving off two “polar 
bodies,” become progamete nuclei. Hach then divides, 
giving two gamete nuclei, which fuse in opposite pairs, to 
form two zygote nuclei. 
It is unfortunate that the recent confirmation of much of 
this remarkable work by Wenyon (07), in HE. muris, has 
failed to corroborate the details of the history of the 
chromidia, 
Entameba histolytica (Schaudinn, 05) appears to have 
a chromidial net like that seen in the Thalamophora.. 
