MORE COMPLICATED LIFE CYCLES 



117 



formed was named bv Herf^-ig. in 1902, ■'chromidien," from which 

 the term chromidia is derived, a term now imlversally employed by 

 protozoologists. According to Hertwig this latter material in actino- 

 spherium cytoplasm is prophetic of the death of the animal, for when 

 it is thus formed the renovation of the cell is impossible 1 19041. 



Arcella vulgaris. 



...Vfier Calkin?.' Three indivi.iuals in plastosamic union. 

 P. idiochromidia: .V. nuclei. 



Fig. 45 











m^^ 



'r-i* 



w 



A B 



Chromidia lormaiion in Actinospherium eiclihornii. vAfter Hertwig.^ .4. primary nuclei 

 and chromidia: B, complete TransformaTion into chromidia. 



It thtis appears that we have to do with two kinds of cliromatin 

 masses in the cell body and no little confusion has arisen in conse- 

 quence of the lULxed terminology applied to this material, which is alike 

 in origin from the nucleus but very different in fimction. Chromidia, 

 in Hertwig's sense, is functionless extranuclear chromatin, but Schau- 

 dinn and others have used the term to designate the sexual cliromatin 

 which is ecjuivalent to the chromidialnetz in Hertwig"s terminolog\". 



