62 



EDMUND B. WILSON 



Fig. 4 Anaphases of first division, all from No. 64; g and h are atypical condi- 

 tions. 



As is the rule throughout the Coreidse, the regular grouping char- 

 acteristic of the first division is usually lost or obscured in the 

 second. As a rule the ring formation is no longer seen, there is, 

 no constantly eccentric chromosome, while the w-chromosome, 

 invariably central in position in the first division, now occupies 

 any position, though* it is more frequently near the center of the 

 group. 



In side views of the metaphases all of these chromosomes, with 

 one important exception, are dumb-bell shaped, and in the initial 

 anaphases are seen drawing apart into a pair of daughter-chromo- 

 somes (fig. 5e-gr). One chromosome, almost invariably central 

 in position, forms an exception in showing no sign of constriction, 

 its form being evenly rounded and often nearly spheroidal. As 



