12 CALIFORNIA ACADEMY OF SCIENCES. 



3. Micronuclei, or conti'acting stage, in which the dif- 

 fused caryoplasin is concentrated at regular intervals, 

 forming a large number of micronuclei. 



4. Caryo kinetic stage, in which the micronuclei fur- 

 ther divide by carj^okinesis. 



In the early stages of the macronucleus the caryoplasm 

 is small in quantity, generally arranged along the inner 

 wall of the caryotheca (fig. '^f)), staining in places more 

 darkly, probably as small chromosomes. 



In the more developed protozoan the caryoplasm fills a 

 large part of the caryosome, is of a streaky, ramified nat- 

 ure, the ramifications evidently proceeding from a center 

 near or around the nucleolus (figs. 7, 41). In unstained 

 specimens the nucleus appears always as a light round 

 spot, with the darker nucleolus in the center. It is first 

 only at a more advanced stage that it takes the stain. 



In the fully developed Spermatobium the caryoplasma 

 stains freely yellow, but not as deeply as the nucleolus. 

 Even a prolonged exposure to h^matoxylon fails to stain 

 it in a distinct way, and it is entirely due to its affinity to 

 orange G. that it becomes well defined. The most in- 

 teresting and striking character of the caryoplasm is 

 its growth, amoeboid extension, budding and division, by 

 which it extends itself far outside of the caryotheca — 

 in fact, diffuses all through or rather between the cyto- 

 spheres. This diffusion of the caryoplasma is undoubt- 

 edly connected with the formation of spores and sporo- 

 blasts, and appears to begin as soon as the Spermatobium 

 is fully developed. Of the very great importance of the 

 caryoplasm in the early stages of the formation of the 

 sporagonia I believe I have made several demonstrative 

 observations. In several instances I have observed how 

 after division one part of the sporogonium remains in 

 an undeveloped state while the other part develops spo- 



