l6 CALIFORNIA ACADEMY OF SCIB;NCES. 



nodes, possibly developing chromosomes, preparatory to 

 final caryokinesis. 



These nodes appear to absorb the outlying caryoplas- 

 mic filaments by which they were at first connected with 

 the mother or macronucleus. During all this radiation of 

 the caryoplasm, the original caryosome appears to be 

 growing in size, and it is able to furnish plasma for forty 

 to sixty micronuclei before diminishing in size, while 

 frequently it becomes much larger than in its early 

 resting stage. Finally, however, the original caryosome 

 generally entirely disappears, though this may not always 

 be the case, as sometimes (as, for instance, in the case 

 figured at loa) a part of the caryosome as well as some 

 cytoplasm remains after the sporoblasts have already 

 been formed. In this figure to the upper left of the nu- 

 cleus is seen a bluish mass, consisting of caryoplasm and 

 unused cytospheres. The nucleus, colored yellow, has 

 evidently contracted its caryoplasmic filaments, as none 

 could be seen either around the remains of the macro- 

 nucleus or around the micronuclei. The nucleolus again 

 has been broken up into one larger and three smaller nu- 

 cleoli. The larger one of these (figured separately io3^ 

 is seen to contain a number of semi-transparent globules 

 of nearly equal size. After the stage in which the cary- 

 oplasmic filaments have been contracted (or disappeared), 

 the small newly-formed micronuclei begin to divide. Pre- 

 vious to this division, however, four important points are 

 to be noticed : 



1. The micronuclei are all of the same size, or almost 

 of the same size. 



2. They are scattered at almost equal distances all 

 through the cytosome of the sporogonium. 



3. The cytospheres become grouped around each nu- 

 cleus in such a way as to form separate little balls or 



