BAUMGARTNER I SPERMATID TRANSFORMATIONS. 49 



The follicles of the cricket testis show the different cell gen- 

 erations and the same relative arrangement of them as Mc- 

 Clung ('00) found in Hippiscus, and Sutton ('00) in Brachystola. 

 The spermatogonia are nearest the blind end of the follicles, 

 spermatocytes next, and the spermatids following the latter. 

 The cells of a cyst are not, as in Anasa (Paulmier, '99) , "in the 

 same stage of development," but only approximately so, for 

 some cysts show cells in the metaphase, while others have 

 reached the telophase. Successive cysts, as in Brachystola, do 

 not show successive stages ; for, frequently, growing spermato- 

 cytes and late spermatids, or even young spermatozoa, were 

 observed side by side. The individual cells in division pass 

 through prophases, metaphases, anaphases, and telophases — 

 these terms being used according to their usually accepted 

 meanings. (See McClung, '00.) In this paper I shall begin 

 with the cell when it has reached the telophase of the second 

 spermatocyte division ; that is, just after the chromosomes have 

 reached the poles of the spindle. 



III. Observations. 



(ft) THE NUCLEUS. 



The chromatin in Gryllus behaves very much as Henking ('91) 

 has described for Pyrrhocoris, and Paulmier ('99) for Anasa. At 

 the end of the anaphase the chromosomes are crowded together 

 at the poles of the spindle. (Fig. 1.) A clear space begins to be 

 formed around them, especially on the equatorial side. (Fig. 2.) 

 They then separate and are scattered somewhat evenly over the 

 nuclear membrane when it is formed, as seen in figs. 4, 5, and 

 6. Soon protuberances appear on the surface of the individual 

 chromosomes, making their outlines irregular. At about this 

 time they begin to show a granular structure. The chromo- 

 somes break up more and more, and soon the chromatin appears 

 in irregularly arranged patches or blotches of granules of vari- 

 ous sizes. (Fig. 8.) 



Meanwhile the nucleus has slowly increased in size. It 

 reaches its maximum, which is probably about treble its original 

 diameter, before the cell begins to elongate. The granules have 

 been breaking up into finer and finer pieces, until, a little after 

 the cell has reached its maximum, the chromatin has largely dis- 

 appeared, or, to be more exact, has lost its affinity for stains. 



