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lapping ends, and the other pairs, one of them simply crossed, the 

 other changing from the parasynapsis arrangement of the earlier 

 prophase to the telosynapsis method of union of the chromosomes 

 in metaphase. Fig. 25, a and b, shows a diflerent method of 

 union of the ends. Thev most often overlap, but may unite 

 and split giving the cross-form so familiar in insect spermato- 

 genesis. Fig. 26 shows an unusually well marked cross; it is 

 the same ring-shaped chromosome with the outer ends separated, 

 the other pairs being already in metakinesis. Fig. 27 is a later 

 stage showing the ring chromosome about to separate later than 

 the other pairs. Figs. 28 and 29 show again both methods of 

 union of the chromosomes in telosynapsis. Fig. 30 is an extreme 

 case of overlapping. Figs. 31 and 32 show two other groups, in 

 each case the group of three being from the same spindle. Fig. 

 33 is a rare case in which all three pairs appeared as rings in the 

 spindle. Figs. 34 and 35 are prophase and metaphase stages 

 from sections. The anaphase in Fig. 36 shows that the over- 

 lapping ends of a pair of chromosomes may remain attached side 

 by side until quite a late anaphase instead of pulhng out into the 

 end to end position seen in Figs. 23 and 31. It is interesting to 

 find in Culex a clear case of parasynapsis in oogonia, oocytes, 

 spermatogonia and spermatocyte prophases, and then to see these 

 same chromosome pairs appearing in the first maturation meta- 

 kinesis as though united end to end (telosynapsis), and not only 

 this, but to be able to trace all the changes from parasynapsis 

 to telosynapsis in some of the preparations. In the Muscid.e the 

 chromosomes pair side to side (parasynapsis), and separate in the 

 first maturation mitosis in a manner closely resembling many cases 

 of longitudinal division, going to the poles in the form of V's 

 while in Culex the pairs become more or less perfectly united end 

 to end (telosynapsis) and then separate as V's. In many cases 

 one can only infer from the position of a pair of chromosomes in 

 the spindle what the method of synapsis has been. In Culex, if 

 one saw only the metaphases and anaphases one would certainly 

 say that it was an undoubted case of telosynapsis, but the fact 

 is that we have here a case of intimate and prolonged parasynapsis 

 somewhat similar to that observed by Strasburger and his school 



