23« 



N. M. Steveris 



Description of Figures 



Fig. 21 Similar stage to Fig. 20, showing transition stages to dumb-bell form. (Ei) 



Fig. 22. Various transition stages from same cyst as Fig. 21. (Ei)^ 



Fig. 23 Tangential section of nucleus in dumb-bell stages, showing heterochromosome pair at. (Hi) 



Fig. 24 Another dumb-bell stage. (Eo) 



Fig. 25 Dumb-bell stage, showing tetrads. (Ei) 



Fig. 26 Tetrads from spindle metaphase and prophase. (Ei) 



Fig. 27 First spermatocyte spindle in metaphase. (Eg) 



Fig. 28 Slightly earlier stage showing the unequal bivalent {pc) out of the equatorial plate. (Hi) 



Fig. 29 "Early metaphase plate. (Ej) 



Fig. 30 Later metaphase plate. (Ei) 



Fig. 31 Metaphase, slightly latei stage than Fig. 27, showing tetrad character of some of the bi- 

 valent chromosomes. (Ei) 



Fig. 32 Equatorial plate showing longitudinal split in some of the chromosomes. (Ei) 



Fig. 33 The heterochromosome pair, showing split in both components. (Ei) 



Fig. 34 Early anaphase. (Hi) 



Fig. 35 Anaphase. (H2) 



Fig. 36 Late anaphase without the lagging chromosome. (Ei) 



Fig. 37 Similar anaphase from same cyst as Fig. 36, with lagging chromosome (^2)- (£1^ 



