264 MICHAEL F. GUYER. 



PLATE V. 



Figures 137, 138, 141, 145, 148-150 are from the Langshan, Fig. 139 from the 

 Rhode Island Red, and the others from the Plymouth Rock fowl. Magnification 

 approximately 2,000 diameters. With the exception of 139 all the drawings are 

 from smears. 



FIGS. 134-149. Side views of division stages in primary spermatocytes show- 

 ing characteristic positions and appearances of the large curved chromosome which, 

 like a typical X-element, passes undivided to one pole of the spindle and thus 

 gives rise to two classes of secondary spermatocytes, one with nine and one with 

 eight chromosomes. 



FIGS. 150, 151. Anaphases of divisions in primary spermatocytes showing the 

 curved chromosome associated with but one set of the daughter autoscmes. 



FIG. 152. Polar view of metaphase in a primary spermatocyte showing the 

 special curved element at one side of the chromosome mass. 



