48 Overton . — On the Organization of the Nuclei i?i the 
essentially similar to that of Allen. Some authors 1 find that the threads, 
although perhaps present in pre-synapsis, first pair during the synaptic 
contraction. According to Gregoire and Berghs there is not a complete 
fusion even in synapsis, but an association of spirems. 
A. and K. E. Schreiner (’05) express the opinion concerning the results of 
Strasburger (’05) , Allen (’05), Miyake (’05), and Overton (’05) that these authors 
have not yet entirely established, either by their descriptions or figures, the 
standpoint taken, viz. that the conjugation is bound up with the contraction 
stage and that the chromosomes do not lose their identity, but appear 
as well formed and well determined structures. Above all, the Schreiners 
contend, one misses the representation of parallel threads in all the figures. 
Certainly one is compelled to admit that the Schreiners have clearly and 
beautifully represented parallel threads for Myxine glutinosa , Tomopteris 
onisciformis , Salamandra maculosa , and Spinax niger in certain stages, 
but the very earliest nuclei do not show such a parallelism of elements. 
It is only later in the history of these nuclei that the threads become 
parallel. To refer to only one point in this connexion, it is difficult to 
understand how a more distinct parallel arrangement of threads could be 
imagined than is shown by Allen’s, Figs. 14 and 15 , PI. II, for Lilium 
canadense , and which is shown for a whole series of plants by my own 
figures, a parallelism so distinct as to even appear diagrammatic to 
Mottier (’07). In comparing the Schreiners' figures with my own I am of 
the opinion that the plants studied and described by me show the parallel 
threads much more distinctly than do the animals studied by them. 
Mottier (’07) maintains that the pre-synaptic nucleus of Podophyllum 
shows no such distinct parallel arrangement of the elements as I have 
described, and cites his figures 1 - 4 , PI. XXVII, to support his views. 
Distinct masses of chromatin are present, with parallel linin threads often 
apparent, and closer examination might very well bring out the condition 
which I have represented. Mottier further believes that there is no definite 
or reliable evidence ‘ to support the prochromosome theory ’ as emphasized 
by Rosenberg, Miyake, and myself. He bases his conclusions upon studies 
of P odophyllum and Lilium. I have distinctly stated in my former paper 
that Podophyllum did not show such chromatin collections, and that the 
individual limits of the prochromosomes could not be distinguished in this 
plant. In this respect Mottier’s conclusions agree with my own. One 
cannot, however, maintain that, because such collections are not present in 
Podophyllum , they do not exist in other plants. I see no reason whatever 
for a change of view, I am still convinced that in Podophyllum , although 
the prochromosomes are not distinguishable, there is a distinct parallel 
arrangement of the linin and chromatin just as I have described it in my 
former paper. 
1 Gregoire (’04, ’07), Berghs (’04, ’05), Miyake (’05), and Tischler (’06). 
