276 Cardiff: Synapsis and reduction 



shows in the late prophases of first mitosis. Farmer and Moore 

 find that the first mitosis is heterotypic and separates the arms of 

 the V by a transverse division through the apex, thus separating 

 whole sporophytic chromosomes. In the second mitosis the divi- 

 sion is longitudinal and separates the parts of the thread formed 

 by the longitudinal split of the earlier stages. Thus there is a 

 true reduction. Farmer and Moore believe that in certain organ- 

 isms the second division may be the heterotypic division, which of 

 course would make no essential difference in the end results. 



Essentially similar results to those of Farmer and Moore were 

 found by Schaffher ('97) in Liliiun, though he does not figure any 

 synapsis (unilateral contraction of the chromatin). In a recent 

 paper Schaffher ('06) in Lilium confirms his former results and 

 states that synapsis is an artifact. So far as I am aware he is the 

 only plant cytologist of the present time holding such a view of 

 synapsis. 



Mottier ('05) upon a reexamination of the microspore mother- 

 cell of Podophyllum concludes again that the first division is a 

 transverse or reducing division. 



Strasburger ('04) gives a peculiar account of synapsis in Gal- 

 tonia candicans. He finds that the sporophytic chromosomes 

 lose their identity during the growth-periods and, in the early 

 mother-cell, the chromatin collects in six centers (Gamozentren). 

 Probably both paternal and maternal chromatin enter these centers 

 which finally elongate to form a spireme. The spireme forms 

 into six segments, each of which is composed of two chromosomes 

 united end to end, and since there are six chromosomes in the 

 gametophyte of Galtonia, these represent the bivalent chromo- 

 somes of the heterotypic mitosis. Thus there is a reduction in 



_ 



the first mitosis essentially in agreement with the results of Farmer 

 and Moore ('05) and Schaffher ( , o6). 



Montgomery ('oo and '01a) in work on Hemiptera, and on 

 Peripatus, a form allied to the myriopods, finds that reduction 

 occurs by an end to end fusion of somatic chromosomes 



in 



the late telophase in the last spermatogonial and oogonial division, 

 that is, with the formation of the mother-cell nucleus. He con- 

 siders this the synapsis stage even though it occurs some time 

 previous to the unilateral massing of the chromatin which he 



