STUDIES ON CHROMOSOMES 393 



known to call for extended review, were substantially at one in the 

 contention that what had been described as a parallel or sidewise 

 conjugation of spireme-threads during the 'bouquet,' 'synap- 

 tene' or 'amphitelie' (synaptic) stage is nothing other than a 

 modified form of longitudinal splitting, in which double threads, 

 longitudinally divided from the beginning, are progressively differ- 

 entiated out of the nuclear substance from one pole of the nucleus 

 towards the opposite pole. In the course of his able critique 

 Meves ('07) endeavors to break down the distinction between 

 such a process and that which is seen in the prophases of somatic 

 cells, contending that in both cases the longitudinal duality is 

 brought about by a biserial grouping of the chromatin-granules 

 of the resting nucleus, and urging that the process seen in the 

 amphitene-nuclei is of essentially the same nature as the early 

 division of spireme-threads in the diploid nuclei long ago described 

 by Flemming. Unquestionably, this objection is worthy of the 

 most attentive consideration, especially in view of the conclusion 

 of several recent observers (considered more in detail beyond) 

 that the longitudinal division of the spireme-threads is in some 

 cases already in evidence in the chromosomes of the preceding 

 anaphases or telophases, and that the two halves thus arising 

 may separate more or less widely before the nuclei have entered 

 the 'resting' state. For Meves there is no problem of synapsis. 

 The Gordian knot is cut with the statement, "Die Geschlechts- 

 zellen bezw. ihre Kerne haben nach meiner Vorstellung (1907) 

 die besondere Eigenschaft ererbt, beim Eintritt in dieWachstums- 

 periode nur die halbe Zahl von Chromosomen auszubilden" 

 ('11, p. 296). Certainly the adoption of this simple solution 

 would save a great deal of trouble; but I fear that the facts com- 

 pel us to take a more roundabout way out of our difficulties. 

 Goldschmidt and Haecker, on the other hand, do not doubt the 

 fact of synapsis, and take issue only with the parasynaptic mode 

 of conjugation. Concerning the latter Haecker's latest expres- 

 sion of opinion is as follows: 



Vielmehr hat sich in mir .... die Ueberzeugung befestigt, 

 dass der Eindruck einer Parallelkonjugation im wesentlichen durch die 

 teilweise Koinzidenz zweier voneinander unabhdngiger Erscheinungen 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 13, NO. 3 



