1897 ] LIFE HISTORY OF LILIUM PHILADELPHICUM 433 
of a single ribbon with an irregular double row of chromatin 
granules (figs. rz, 13). At some point in this stage the so- 
called “synapsis” is said to occur. The chromatin loops now 
break apart and lie free in the nuclear area, while at the same 
time the nuclear membrane has almost entirely disappeared. 
Wherever the chromosomes were counted they were twelve in 
number. Thus it will be seen that the spirem first undergoes 
complete longitudinal fission and then breaks up into half the 
number of loops or chromosomes that are present in the cells of 
the sporophyte. The important feature in this pseudo-reduction 
of the number of chromosomes in the nucleus is not so much 
the fact that the spirem is cut into twelve parts as that it twists 
into twelve loops which predetermine the twelve divisions and 
the twelve chromosomes. The chromatin loops or chromosomes 
are not all of the same size. Indeed, there is often considerable 
difference in the lengths of the several chromosomes. In this 
way there may be considerable diversity in the subsequent 
reduction of the chromatin granules. Each chromosome then 
represents a double twisted chain of chromatin granules, and 
this double thread twisted on itself, so as to make one end of 
the chromosome a closed loop and the other with two limbs 
more or less free. 
In the meantime the nucleolus becomes filled with a large 
number of small vacuolate bodies. Each of these bodies has a 
dark outer part with a light refractive center. Small bodies 
exactly like those within the nucleolus appear in the nucleus, 
and as soon as the nuclear membrane has disappeared some of 
these are also seen in the surrounding cytoplasm (figs. 14, 15). 
The formation of these micronucleoli occurs as follows: The 
nucleolus sends out a papilla-like projection, into which one of 
the vacuolate bodies enters and is then separated from the 
nucleolus by abstriction (figs. 76-20). The micronucleoli are 
es thus all separated from the mother nucleolus by a process of 
budding. Just about the time when the indiv ridual chromosomes 
ate. formed and the nuclear membrane disappez 
| Eeiehons baits all around he _onieien “These threads ae ou 
rs, cytoplasmic = 
