282 C. CLIFFORD DOBELL. 
logical foundation; chromidia, used generally, like Gold- 
schmidt’s “chromidia in the wider sense”; tropho 
chromidia, for chromidial structures of a vegetative func- 
tion; idiochromidia, for chromidia which enter into the 
formation of gametes.1 
Schaudinn’s (’05) three parallel terms are chromidia, 
somato-chromidia, gameto-chromidia, Other writers 
use various paraphrases of these, such as ‘‘somatic chromidia,” 
” “vegetative chromidia”’; and “ gametic 
“trophic chromidia, 
chromidia,” “generative chromidia,” ‘“ propagative chro- 
midia,”’ ete. 
I will mention only one more term, used by Calkins (’05)— 
protogonoplasm. This unwieldy word is used to designate 
chromidia taking part in gamete formation. The self- 
explanatory term “ distributed nucleus” is also used by this 
writer, though similar expressions (e. g. “diffuse nucleus ”’) 
have long been in use. 
Ik 
I will now endeavour to summarise the state of our know- 
ledge regarding the existence of chromidia and _ their 
probable function in the Protista (Protozoa and Bacteria) 
and Metazoa. My aim here is to give facts, and to steer 
clear of hypothesis for the present. 
(aA) CHromipra In Prorozoa. 
(1) I will begin with the Heliozoa, as the chromidia 
hypotheses largely took root in this group. I refer, of 
course, to the magnificent researches of R. Hertwig on 
Actinospherium. From the immense mass of detail 
discovered by Hertwig and his school I select the following 
facts : 
Hertwig (99a) gave the first description of chromidia in 
1 Cf. Lubosch’s (02) terms, “trophochromatin” and ‘ idiochro- 
matin.” 
