CHROMIDIA AND THE BINUCLEARITY HYPOTHESES. 299 
have their chromatin in a chromidial condition. (Cf. also the 
morphology of Achromatium, as carefully studied by 
Schewiakoff, 793.) 
In large bacteria which have been carefully studied, the 
chromidia are seen to come together to form a nucleus-like 
body during spore formation (cf. Schaudinn ’02, ’03a; 
Dobell, 08; Guiliermond, ’08, etc.) (text-fig. 17). 
It appears equally certain, however, that some bacteria—or 
organisms at present classified as such—possess a _ well- 
differentiated nucleus, and not chromidia (Vejdovsky, Mencl, 
etc.). The nucleus may sometimes be in the form of a 
filament or otherwise modified. 
So much for the true bacteria. We may here consider, as 
an appendix to them, that interesting little group of protists, 
Trxt-riec. 17. 
Bacillus flexilis. The nuclear apparatus is seen to consist 
of chromatin particles scattered through the cytoplasm. 
(Original.) 
the spirochets. In some, at least, of these the chromatin 
appears to be arranged, wholly or in part, in the form of 
chromidia. I wili give Spirocheta plicatilis as an in- 
stance. In this organism, ‘‘ The nuclear apparatus consists 
of a thread-like structure running in the long axis 
whilst the vegetative nuclear mass surrounds this thread in 
the form of granular chromidia ” (Schaudinn, ’05a). 
(c) CHromipra In Merazoa. 
Descriptions of free chromatin particles in metazoan cells— 
homologized with the chromidia of the Protista—are not few. 
The two most important cases—the two which I shall chiefly 
discuss here—are the chromidia of the tissue-cells of nema- 
todes, and the chromidia in the gametogenesis of gastropods. 
‘These are the mainstays of the arguments, in favour of the 
chromidia hypotheses, derived from multicellular organisms. 
