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The researches lately carried out at the Botanical Labora- 

 tory at Bonn have especially called attention to these aggregations 

 of chromatic material in the præsynaptic period of the first mitosis 

 in the PMC. It has been observed, that their number is about 

 the same as that of the chromosomes. Overton (19) has given 

 them the name of prochromosomes and they can well be likened 

 unto the „pseudonucleoles" which I pointed out were to be found 

 in somatic nuclei where their number is the same as that of the' 

 chromosomes (Bosenberg 24). Overton has also carefully 

 studied these bodies in somatic cells as well as in the gonotokonts. 

 In Thalictrum, Helleborus, Campanula and others such bodies could 

 clearly be observed and their number decided to be the same as 

 that of the chromosomes! In very young nuclei, for instance in 

 the cells of the embryo such bodies are not clearly found, while 

 in older resting nuclei they are often observed. 



At a later stage in the PMC these bodies come closer together, and 

 the linin lies more densely around the bodies two and two (fig. 3). 

 I have in many cases been able to fix their number at 9. Figs. 2 

 and 4 show these chromatic bodies or chromosomes, as we are 

 now able to say, at a later period collected together at one side 

 of the nucleus, clearly a beginning of the synapsis stage. It is 

 noteworthy, that the nucleolus is now only one, and a careful 

 examination of several different stages shows, that this single 

 nucleolus has been formed by the union of the two aforementioned 

 nucleoli. At an early stage this nucleolus is more drawn out or 

 ellipsoidic, but later it becomes rounded. This appearance of the 

 nucleolus certainly depends not entirely upon its soft condition at 

 this stage (compare the „Sichelstadium") which has become con- 

 firmed by many different stages which I have been able to 

 observe. 



The further development ot the chromosomes seems to corre- 

 spond with the description of this phenomenon which Miyake (9) 

 and Overton (19) have given of it in other plants. 



The prochromosomes never entirely become united, but as far 

 as I have been able to discover, one can always discern the double 

 nature of these bodies. Thereupon they are almost broken up into 

 many small bodies which are spun out along the linin threads. 

 At the close of the synapsis stage, this is quite clearly seen, 

 whereupon the parallel arrangement of the threads is also evident 

 (flg- 5). 



