PLATE 1 



EXPLANATION OF FIGURES 



First spermatocyte division stages 



1 Equatorial plate with four projecting arms. 



2 a Equatorial plate with one projecting arm. 



2 b and 2 c Metaphase spindles, each with a very small separate chromosome. 



3 a Equatorial plate, chromosomes closely massed together. 

 3 b Metaphase spindle with no X-chromosome. 



3 c Anaphase with projecting arm at the left pole. 



4 Equatorial plate with a round chromosome to the left and a rod to the 

 right. 



5 Equatorial plate with a rod to the right. 



6 a Equatorial plate, chromosomes much scattered. 



6 b Anaphase with no possible X-chromosome. 



7 a Equatorial plate, chromosome is fused. 



7 b Equatorial plate, chromosomes in two nearly equal masses. 



8 a Metaphase spindle with no possible X-chromosome. 



8 b Equatorial plate, large separate i-od. one-third the size of whole chromo- 

 some mass. 



9 Equatorial plate, T'-shaped chromosome to right. 



10 Equatorial plate, two separate chromosomes, one round to left, and one 

 three-parted to right. 



11 a Equatorial plate, one round chromosome to the right. 



11 b Equatorial plate, separate round mass, one-third the size of the whole 

 chromosome mass. 



12 a Equatorial plate, no possible X-chromosome. 



12 b Equatorial plate, two separate round chromosomes to the right. 



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