712 C. E. McCLUNG ' 



Similar views with regard to the rings are held by Sutton, 

 Pinney, Stevens, Robertson, Granata, Nowlin and Carothers. 

 In the accounts and figures of these investigators is found sub- 

 stantial confirmation on each of the points of observation that 

 I have just discussed. It is important to note here that among 

 these are careful detailed studies of the rings in the prophase 

 and representations of them not only in lateral view but also 

 from above and en face. Such aspects of the rings are conspic- 

 uously lacking in the figures of those who favor the other explana- 

 tion of ring formation and division. The numerous tabulated 

 drawings of chromosome complexes in polar view by Robertson 

 demonstrate the almost uniform occurrence of the rings in the 

 equatorial plate — a circumstance that is not mentioned by the 

 advocates of prereduction. 



The second form of explanation of the behavior of the rings in 

 the first spermatocyte was advanced by de Sinety and was later 

 endorsed by Montgomery, Davis, Buchner and Brunelli. It 

 contradicts the one just discussed in these points: (a) The rings 

 lie in the axis of the spindle and are visible on the margin of the 

 complex in lateral view (de Sinety, fig. 131; Buchner, fig. 55; 

 Montgomery, fig. 23 ; Davis, figs. 63 and 64) ; (b) fiber attachment 

 is opposite the synaptic ends (de Sinety, figs. 123, 131; Buchner, 

 fig. 55; Montgomery, fig. 33; Davis, fig. 63); (c) the synaptic 

 ends are directed away from the spindle axis; (same figs, cited 

 under h) ; (d) the plane of chromosome separation lies perpen- 

 dicular to the equatorial plate (Sinety, fig. 312; Montgomery, fig. 

 33); (e) whole univalent chromosomes separate from each other; 

 (f) they pass across the equatorial plate and go to the pole 'on the 

 opposite side (Sinety, fig. 131; Buchner, fig. 55; Montgomery, 

 figs. 32 and 33; Brunelli, figs. 14 and 15); (g) the diverging ends 

 of the chromosomes to which the fibers attach do not lie super- 

 imposed but are displaced laterally (no views en face are given by 

 any advocates of this method) and there would be no resemblance 

 to the crosses or V's regarded from the same point of view. The 

 two interpretations may fairly be contrasted by saying that, 

 according to the first, uniformity of relations throughout the cell 

 generations, and between elements of the complex, is preserved; 



