324 THOS. H. MONTGOMERY, 



of all the chromosomes together constituted a continuous linin spirem, 

 so we may say that in the prophases of the first maturation mitosis 

 this spirem still persists, and that accordingly it had persisted through 

 the rest stage. The direct evidence for the persistence of these linin 

 threads in their original connections, i. e. for the persistence of the 

 linin spirem, in these prophases is as follows. Whenever in the early 

 prophases the central ends of the two univalent chromosomes, which 

 together compose a bivalent one, lie in the same plane of view, a 

 direct connection between these ends is seen to be formed by a 

 distinct linin thread, which is in every way comparable to that of the 

 preceding synapsis and telophase. Then whenever a univalent chromo- 

 some is seen strictly laterally its distal end may be seen to be con- 

 nected with a linin thread usually of greater length than the other; 

 this is directly referable to the distal thread of the chromosome of 

 an earlier stage. Portions of the axial thread of the chromosome can 

 be seen in very early prophases (Figs. 133, 134), and the reason why 

 it cannot be seen later is simply that the deeply staining chromatin 

 becomes evenly distributed along it. Now this axial thread passes 

 continuously at one end into the central thread, at the other into the 

 distal thread : the three together form one continuous thread, exactly 

 as in the synapsis, and in the composition of a bivalent chromosome 

 we have accordingly a continuous linin thread made up as follows: 

 distal thread, axial thread, central thread, axial thread, distal thread. 

 Further, it can be clearly seen in some cases that a distal thread of 

 one bivalent chromosome passes continuously over into a distal thread of 

 another bivalent chromosome (Figs. 147, 149, 155—159, 161, 165, 167). 

 Thus a direct continuity can be observed in the linin connection 

 between two chromosomes. Now since the distal end of one bivalent 

 chromosome has in several cases been observed to be united by a 

 linin thread with one of the distal ends of another bivalent chromo- 

 some, I conclude that all the chromosomes in the nucleus are so con- 

 nected, and that, accordingly, the thicker of the linin threads present 

 in the nucleus together constitute a continuous spirem. The inter- 

 chromosomal fibres would then be the distal fibres, while the linin 

 connections between the two univalent chromosomes of a bivalent one 

 would be effected by the central fibres. In the diagrams 253—226, 

 Plate 25, these two systems of fibres have been shown in red, while 

 the axial fibres have not been delineated. 



It may be objected to the conclusion just stated, that I have not 

 directly observed, and show nowhere in my figures, a linin thread 



