562 Mot?rrieER AND NOTHNAGEL: CHROMOSOMES OF ALLIUM 
threads and not expressions of osmotic currents. In fact it 
seems extremely difficult to bring any of these phenomena under 
explanations based upon osmotic activity. 
On arriving at the poles, the chromosomes become closely 
crowded together in a manner well known for nearly all plants. 
In the organization of the daughter nuclei, the chromatin does 
not pass into the finely divided state by the processes of reticu- 
lation, alveolization or fragmentation as is characteristic of many 
gymnosperms and dicots. The various segments do elongate, 
however, to three or more times their original dimensions, be- 
coming somewhat lumpy or irregular in outline, and finally form a 
sort of interrupted spirem which is seen as a series of longer or 
shorter loops or turns passing from the pole to the anti-pole side 
of the nucleus (Fic. 22). This figure represents a daughter 
nucleus seen somewhat obliquely from the polar side. The course 
of the spirem is usually more irregular than in this figure, there 
being many more short and abrupt genuflections or kinks. We 
have spoken of this spirem as discontinuous, for the reason that 
what are regarded as free ends can be found. These free ends are 
sometimes joined by very delicate threads like the anastomosing 
threads extending between parallel parts of the spirem in all cells 
whether purely vegetative or sporogenous. If the apparently 
free ends were connected by thicker threads, the spirem could 
then be spoken of as continuous. Whether or not this spirem 
is continuous or interrupted is of no theoretical importance. 
The side of each loop, or turn, is wavy or zigzag, due, of course, 
to the lack of space in the nuclear cavity for the placing of the 
greatly elongated segments. Whether continuous or interrupted, 
the whole forms a sort of crown or wreath open both at the pole 
and anti-pole sides. We assume that the adjacent or parallel 
sides of the loops are homologous with the sides of the U's or V's 
that pass to the poles during the previous anaphase. We do not 
find that the loops or ends of this spirem unite at the polar side 
to form ‘“‘Chromatinknoten”’ either in these nuclei or in somatic 
cells that are normally preserved. A comparison of a daughter 
nucleus (FIG. 22) with a granddaughter nucleus (Fic. 23) shows that 
the arrangement of the chromatin is similar and that it is due to 
similar causes which may be and probably are purely mechanical. 
