PLATE 2 



EXPLANATION OF FIGURES 



13 to 18 a First spermatocyte metaphase spindles 



13 Extra arm to left toward upper pole. 



14 Small round separate chromosome toward lower pole. 



15 and 16 Round chromosome projecting from the mass toward the lower pole. 



17 a and b No possible .Y-chromosome present. 



18 a No possible X-chromosome present. 



18 b to 21 First spermatocyte anaphases 



18 b Left pole of spindle more clearly in focus than right ; at least one of 

 three projecting arms at the left has a corresponding arm at the right. 



19 Two projecting arms at upper pole, and one at the lower. 



20 No possible A'-chromosome. 



21 Projecting arm at right of both upper and lower poles. 



22 and 23 Second spermatocytes 



22 a Equatorial plate, rod to left. 



22 b Metaphase spindle, small round projection toward lower pole. 



22 c Equatorial plate, no possible A-chromosome. 



22 d Equatorial plate, separate round chromosome to left. 



23 a Anaphase, no possible X-chromosome. 



23 b Metaphase spindle, small round projection toward lower pole. 



74 



