Evldcucc from Protozotnis 385) 



tips, togctlicr inakiiio- a sort of })anvl-.slia|)((| collar. 'I'Imv 

 become deeply colored when treated with miclcar stairi>. 

 while the fibers above described remain nearly or (juitc un- 

 stained. "The myophrisks do not insert, as previouslv d<- 

 scribed, by their })roximal ends into the superficial .cto- 

 plasmic layer, and by their distal ends into the spines, but 

 lie in the puUino- fibers." ^^ 



The developmental point made out is that the myophrisks 

 arise from chromatic material lyino- in the central capsule 

 and migrate out to their definite ])ositions (///.//'., figure ^fi). 

 The origin takes ])lace, according to the authors, in two 

 ways. By one method the entire nucleus of a nierozoite 

 transforms into the myophrisk; by the other, the chromatic 

 bodies of the macronuclei unite to ]n'oduce these structures. 

 Numerous details are given of the development and structure 

 of the myophrisks which we can not enter into. Enough 

 is it to recognize the direct part ])layed by chronjatic sub- 

 stance in the production of these bodies. 



Now comes the point which specially concerns the pres- 

 ent discussion: The authors believe, from observations of 

 their own, that Richard Hertwig's su])position that the 

 bodies are contractile, is correct. Assuming this to be tlu'ir 

 office, and assuming the authors to be right in their account 

 of the relation of the bodies to the pulling fil)ers aiui of the 

 fibers to the spines, we have here a composite apparatus 

 consisting of the spine, the ])ulling fibers, and the contrac- 

 tile elements, one portion of which, the contractile, is de- 

 rived from chromatic substance, and two ])()rtions, the spine 

 and the pulling fibers, are derived from non-chromatic sub- 

 stance. A slight reservation must be made- in the |)art of 

 this statement which concerns the s])ine and the fibers in 

 that w^e are without direct observational knowK-dge as to 

 the origin of the spines and the fibers. However, it is ahno>t 

 certain that the fibers are entirely differentiations of extra- 

 capsular plasm; and that the spines are at least i)artly of 



