m'clung: spermatocyte divisions of the locustid.k. 189 



reticular structure, with such large intervening hyaloplasmic 

 areas as to suggest an almost alveolar structure, especially in 

 the later stages (figs. 3-9) . This increased amount of fluid be- 

 comes evident by an examination of sections under even a low 

 power of the microscope, principally by the lessened density of 

 the general stain in the cell. 



A peculiarity of the archoplasm in these early prophases is 

 the persistence manifested by the spindle fibers of the previous 

 generations. Often connecting fibers may be seen, joining cell 

 to cell, as has been described by many writers, but, in addition 

 to this, the spindle remains of more remote ancestral mitoses 

 show themselves. In figure 3 is represented a cross-section 

 through three persisting spindles of as many generations. 

 Their age is suggested by size and intensity of stain, both fac- 

 tors being least marked in the oldest structure. 



Centrosomes and astral radiation do not present themselves 

 with the prominence and frequency of such structures in corre- 

 sponding cells in Hippiscus. 



The main interest of these studies, however, attaches to the 

 movements of the chromatin granules. As was suggested in 

 an earlier paper (17), it is only by an understanding of the 

 constructive processes in the prophase that we can appreciate 

 the structure and changes of the chromosomes in the meta- 

 phase. It is to this period in the history of the chromosomes 

 that I have given the most attention and to which I will devote 

 the most space in the record of observations. 



Apparently the chromomeres resulting from the disintegra- 

 tion of the spermatogonial chromosomes are loosely scattered 

 through the nucleus, so that no formed structure is to be seen. 

 With the increase in size of the cell, however, a linear arrange- 

 ment of the elements becomes apparent, so that it seems as if 

 a thread is formed. Whether this is continuous or segmented 

 it is not possible to determine. The large amount of chromatin 

 and the tortuous course of the filaments put a solution of the 

 problem beyond the range of assured observation. It is with 

 much regret that this fact is recognized, for one of the most 

 important questions connected with the maturation mitoses 

 hinges upon the method by which the chromosomes, as such, 

 are derived from those of the spermatogonia. Upon this point 

 the evidence of the ordinary chromosomes of these cells would, 



