THE NUCLEUS 



35 



formation of chromosomes during division, and hence may play an 

 active role in the nuclear activity. Strasburger ('95) likewise be- 

 lieves them to contain a store of active material which, however, has 

 no direct relation to the chromosomes but consists of " kinoplasm " 



VuMiiLvH^ 



C E 



Fig. 14. — Special forms of nuclei. 



A. Permanent spireme-nucleus, salivary gland of Chironotnus larva. Chromatin in a single 

 thread, composed of chromatin-discs (chromomeres), terminating at each end in a true nucleolus 

 or plasmosonie. [BalbiaNI.] 



B. Permanent spireme-nuclei, intestinal epithelium of dipterous larva Ptychoptera. [Van 

 Gehuchten.] C. The same, side view. 



D. Polymorphic ring-nucleus, giant-cell of bone-marrow of the rabbit; c. a group of centro- 

 somes or centrioles. [Heidenhain.] 



E. Branching nucleus, spinning gland of butterfly-larva {Pieris) . [KORSCHELT.] 



(p. 322), from which arises the achromatic part of the division- 

 figure (p. 82). On the other hand, Hacker ( '95, '99) and other 

 observers regard the nucleolar material as a passive by-product of 

 the chromatin-activity destined to be absorbed by the active sub- 



