178 W. WALDEYER. 
chromatic loops, so that the process which was commenced 
in the previous stage will be completed at the beginning of 
this stage, and in a very remarkable and interesting way. 
The chromatic threads follow the equator of the spindle figure, 
and here group themselves close together in the way already 
described. If one looks at a nucleus from one of the poles of 
the spindle, the chromatic figure will appear as a star with a 
a clear centre, in the middle of which is a second star, the pale 
spindle figure, from the pole of which one is looking (fig. 8). 
The longitudinal splitting is accompanied by a shortening and 
a thickening of the threads. 
This stage lasts for only a short time, and quickly passes into 
the following, which is now termed by Flemming “ metakinesis.”! 
In this there is accomplished, essentially, the separation of 
the chromatic sister-threads resulting from the previous longi- 
tudinal splitting. EH. van Beneden (28) was the first to show 
with certainty in animal-cells (segmentation of the egg of 
Ascaris megalocephala), and Heuser (97) at the same 
time in plant-cells, that of the two secondary threads (sister- 
threads) which arise from one original chromatic primary 
thread, one goes to one pole of the nuclear spindle, and the 
second to the opposite pole. Next to the recognition by 
Flemming of the longitudinal splitting of the threads, these 
discoveries by van Beneden and Heuser are certainly the most 
important which have been made on the subject of karyo- 
1 The expressions “ equatorial plate ’” (Flemming), ‘‘ nuclear plate” (Stras- 
burger), are, on account of the word “ plate,” best suited to the end of the 
monaster stage, when the chromatic elements are collected together in 
one plane at the equator. The word “ metakinesis” is better used for 
the next stage, in which the halves of the loops begin to separate from one 
another; it does not quite correspond to the term “ equatorial or nuclear 
plate.” The word “ plate” is moreover not particularly descriptive of a struc- 
ture formed of loops; in some cases, namely, in plant-cells, it happens that the 
chromatic threads are very short and resemble granules ; such thread-elements - 
lie close together nearly in one plane, so that certainly the impression of a 
“plate” is conveyed. Mayzel, in his work already mentioned, represents such a 
condition in the spermatocytes of Liparis and Sphynx-larve, and in other 
animal cells. He described them previously (1881). Recently Platner has 
described similar structures in his work on karyokinesis in Lepidoptera (161). 
