4O J. E. WODSEDALEK. 



EXPLANATION OF PLATES. 

 PLATE I. 



(All of the drawings were made with the aid of a camera lucida, X 3,000.) 



FIG. i. Early spermatogonial cell showing a large heart-shaped nucleolus and 

 two small karyosomes. 



FIG. 2. Resting stage of a full grown spermatogonial cell showing the large 

 triangular or heart-shaped nucleolus and the two spherical karyosomes. 



FIG. 3. Late prophase of spermatogonial division showing fifty ordinary chro- 

 mosomes and the large accessory which can easily be distinguished. 



FIG. 4. Metaphase of division in a spermatogonial cell showing a perfect spindle 

 with the accessory dividing at the left. 



FIG. 5. Anaphase of division of a spermatogonial cell showing a perfect mitotic 

 figure. 



FIG. 6. Late anaphase of division of a spermatogonial cell with perfect mitosis 

 again in evidence. 



