408 Sidney I. Kornhauser 



somes (s.S.) withoiit a "Querkerbe" form another pair, which is con- 

 spicuous, also, in the second spermatocytes and oöcytes. AVhen the 

 longitudinally cleft chromosomes with "Querkerbe" are tilted in the 

 plate (upper left, Fig. 8), they appear as "tetrads". This fact is of impor- 

 tance, in as much as the appearance of "tetrads" in soma, cleavage and 

 primordial germ-cells has been used as an argument against syndesis 

 and the significance of tetrad formation. 



In the cytoplasm of the metaphase stage lie the cyto-plasmosomes. 

 The attachment of the spindle fibers to the chromosomes is usually me- 

 dium and the sister chromosomes of the anaphase (Plate V, Fig. 9), 

 in passing to the poles, form V's. Often in the late anaphase the chro- 

 mosomes lie so nearly in one plane, that, in polar view, a count of their 

 apices is not difficult. The result of such counts is twenty-four in 

 most cases, twenty-two or twenty-three in others. Never however did 

 the count approach the reduced number. The cyto-plasmosomes seem- 

 ingly have no direct connection with the centrosomes, and are distributed 

 by Chance to the two sister cells, one often receiving many more than 

 the other. The telophase chromosomes become gradually fainter in 

 outlines (Plate V, Fig. 10), and a clear area in the cytoplasm begins 

 to form about them. It is, I beUeve, the boundary between this clear 

 area and the more reticular cytoplasm which forms the new nuclear 

 membrane. The chromosomes, scattered through the newly formed 

 nucleus, send out processes, and only several granules in each remain 

 deeply stained. The cyto-plasmosomes {cpL, Plate V, Fig. 11) are found 

 against the nuclear membrane, and within the nucleus there are as yet 

 no nuclcoli. 



B. Oögonia. 



The division of the oögonia occurs only in that portion of the tube 

 which irnmediately borders the "Keimpolster". The phenomena of mi- 

 tosis are practically the same as those described for the spermatogonia, 

 except that one nucleolus, instead of two, characterizes the quiescent 

 nucleus. The prophase chromosomes do not form froni the segmentation 

 of a spireme, nor do the telophase chromosomes form a spireme before 

 they become indistinct. Here also (Plate VI, Fig. 44) the diploid 

 number, twenty-four chromosomes, are present, most of which show a 

 distinct "Querkerbe", The short pair without transverse suture (s.s.) 

 is also recognizable. 



The facts presented for Hersilia are supported by observations on 

 Diaptomus coeruleus. After Hermann's fluid fixation, the spermato- 



