Nov., 1914] 
Stamens of Smilax herbacea. 
359 
spirem was discernible at this time and at intervals the spirem, 
which is made up of previously paired chromatin elements, was 
constricted in some places to a narrow thread and finally separated 
into irregularly shaped double segments. These pieces continue 
to thicken and shorten, forming X and V-shaped chromosomes. 
She says that the first division is merely a separation of the 
chromosomes, but the second is a true mitosis. At the telophase, 
she observed that the spirem was disposed about the periphery 
of the newly formed membrane. The nuclear membrane dis¬ 
appears and the spirem is spread out over the spindle and in a 
short time the spirem contracts into the equatorial plane, dividing 
into chromosomes which become attached to the spindle with 
the open ends outward. She could not determine the exact 
number of chromosomes, but decided that there were either 
twelve or thirteen. 
Schaffner found in his study of Erythronium that the spirem 
was at first long, slender, with chromatin granules that are not 
prominent before the looping. The spirem undergoes a contrac¬ 
tion and a preceptible thickening, and is thrown into twelve 
loops which are apparently broken apart by the twisting and 
contracting. The chromosomes are said to be of various sizes 
and seem to be double. They are attached to the spindle near 
the free ends and during metakinesis are uncoiled and pulled 
apart in the middle. 
In Lilium tigrinum, (13), he found the chromatin network 
forming a thin spirem with a single row of spherical granules. 
There were no free ends so this would point to the fact that the 
spirem is continuous and is also free in the cavity. The spirem 
was then found to be in a condition of contraction and there 
was not any apparent change in the spirem after it had come out 
of this condition. After this the linin thread is said to elongate. 
The spirem also has a tendency to form into loops. Twelve 
loops are formed which break up into twelve chromosomes. 
These are attached to the spindle fibers near the free ends in the 
mother star and are separated by a transverse division. The 
split in the second division is a longitudinal one. 
When working with Agave virginica (15), he found that 
there was a course chromatin net present and the cytoplasm 
was dense and spongy. The chromatin net stretched out and 
formed bivalent protochromosomes which in turn formed a 
delicate spirem with a single row of granules. Synizesis fol¬ 
lowed, and in a study of the living material no contraction of the 
chromatin material was noticeable. After synizesis a transverse 
division of the chromatin granules takes place with a shortening 
and thickening of the spirem which is thrown into loops of various 
sizes and pressed against the wall of the nuclear cavity. With 
the breaking of the spirem there results three ring chromosomes, 
