A HUNDRED MICROSCOPICAL OBJECTS 



221 



lanceolata, too, gives excellent preparations of chromomeres 

 by this method. (Wenrich, Gelei, Belling.) 



5. Contraction of the Pachytene Bivaients in Agapanthus 

 and Kniphofia. — Young anthers of Agapanthus umhellalus 

 and of Kniphofia aloides at the right stage are dried with 

 filter paper, smeared, fixed with chrom-acetic-formalin for 

 2 to 5 hours, mordanted for 24 hours, stained with iron- 



FiG. 25. — Pollen mother cell of Agapanthus umbellatus, showing the pachyteni> 

 coils. The 15 bivaients are thickened around the points of constriction where 

 there is a special corpuscle. The chromomeres are visible. Fixation, etc. as 

 in Fig. 24. Camera drawing. 



brazilin for about 2 hours, shghtly differentiated, and 

 mounted in immersion oil. Selected cells are slightly flat- 

 tened by due pressure on the cover-glass. In Agapanthus, 

 15 thickenings at the pachytene stage are usually to be 

 observed, corresponding to the 15 bivaients. Most biva- 

 ients will show a clear constriction with one (or two) 

 polar granules in it. In Kniphofia six such thickenings 

 are readily visible, corresponding to the six bivaients. 

 (Belhng.) {See Fig. 25.) 



6. Numbers of Chromosomes in the Pollen Grains of 

 Triploid Hyacinths.— The bulbs of the triploid hyacinths 

 are usually at the right stage (late in October or) early in 

 November. (King of the Blues is rather late.) The 

 bulbs can be kept dry and cut open when required, or they 



