THE SPERMATOGENESIS OF AGALEXA N.KVIA. 135 



together at this point. In iron-hsematoxylin preparations the 

 bend of the loops takes a deeper stain than the other portions 

 do, while in safranin and gentian violet preparations the chromo- 

 meres at the bend of the loops take the safranin and the arms of 

 the loops stain violet. Since condensed chromatin always does 

 take the safranin, this differential staining may indicate merely a 

 compact structure due to the mechanical bending of the loop but 

 it may also indicate the junction of homologous chromosomes. 

 In the light of the above facts, I consider it highly probable, 

 therefore, that the split in the spireme represents a precocious 

 longitudinal division which is more or less visible throughout the 

 prophase of the first maturation division. 



The succeeding steps are as follows : The longitudinally split 

 loops become shorter and consequently thicker, drawing down 

 toward the distal pole. The bend becomes acute, forming V- 

 shaped chromosomes which split from apex to base along the 

 line of the original longitudinal split and open out into double 

 Vs. At this point the chromosomes can be easily oriented for 

 the split extends entirely through the free extremities of the arms 

 of the V while the apices show the compact structure character- 

 istic of the bend of the spireme loop. When they have taken up 

 their final position at the equator of the spindle, one has no 

 trouble in determining with certainty that the angles which cor- 

 respond to the bend of the loop lie in the plane of division, while 

 the angles corresponding to the free ends of the loop are directed 

 to the opposite poles. Still further assurance, if needed, is gathered 

 from the fact that sometimes a chromosome, which has not yet 

 opened out, is drawn into the equator of the spindle and there 

 always lies with its apex in the equatorial plane and its free ends 

 directed toward the poles. Later this single V opens out into a 

 double V preparatory to division. The first division then takes 

 place through what corresponds to the apex of the original V- 

 shaped chromosome and if this represents the point of union 

 between the homologous elements, the first division must be 

 reductionial. 



In the V-shaped chromosomes of the telophase, the space be- 

 tween the two arms corresponds to the split which first appears 

 precociously in the spireme. When, in the succeeding division, 



