GERM CELLS IX PEDICELLINA AMERICANA 27 



pointed out in the discussion of the early prophases that the 

 bivalents appeared, first, as elongated bars with a split running 

 the length of the bar and, second, as rings of various forms. 

 The latter, in their further development, are often converted 

 into bars of the first type or into cross-shaped figures ; but in 

 both of the two main types, whatever be the individual pecu- 

 liarities, it is clearly seen, in the light of the earlier stages of 

 oocytic growth, that the space running along the long axis of 

 the figure is the longitudinal split separating sister bivalents. 

 The ends of the bars would then be the longitudinal ends and 

 the points intermediate at the middle on the sister bivalents 

 would thus be tne points of synapsis. A division, therefore, 

 which passes through the former points would be longitudinal, 

 while one passing through the latter would be transverse or 

 reducing. 



In Pedicellina, it is quite evident that the second of these 

 conditions is the actual one. In every instance of the consid- 

 erable number of late prophases and metaphases examined, I 

 have found the rods so placed that their long axis corresponded 

 with that of the spindle. The points of synapsis are, therefore, 

 in the equator and the division which now ensues passes through 

 these points, and separates the univalent chromosomes which 

 had remained united since the last oogonial telophase. In this 

 regard, the conditions in Pedicellina agree with the early obser- 

 vations of Henking, '90, on Pyrrochoris, Paulmier, '99, on 

 Anasa and those of Montgomery, who in Peripatus and a large 

 number of other forms, always found the first the reducing 

 division. On the other hand, these results are opposed to the 

 conclusions of Ruckert, '94, and Hacker, '95, and '02, on the 

 Copepods, of VomRath, '92, on Gryllotalpa, of Griffin, '99, on 

 Thalassema, and the more recent ones of Sutton, '02, on 

 Brachystola, according to whom the first division is longitudinal. 

 > The dyads resulting from the first division are, in the main, 

 of one form in the early anaphase as were the tetrads in the 

 metaphase. As Fig. 95, ^ and b, shows, there is often present 

 a thin strand of chromosomal substance connecting the dyads 

 across the center, but this soon disappears. In no case have I 



