448 ROBERT T. HANCE. 



DESCRIPTION OF PLATE I. 



All figures were drawn at table level with a Zeiss 1.5 mm. apochromat and a 

 15 X Orthoscopic ocular. They are reproduced at the size originally drawn. 

 All are polar views of metaphase plates in chick embryonic cells with the exception 

 of Fig. 5. 



FIG. i. From optic cup. 35 chromosomes. 



FIG. 2. From amnion. 30 chromosomes. 



FIG. 3. From a male gonad. 39 chromosomes. 



FIG. 4. From neural tube. 32 chromosomes. 



FIG. 5. Late prophasc in connective tissue cell grown in a tissue culture. 

 38 chromosomes. 



FIG. 6. From heart muscle. 33 chromosomes. 



FIG. 7. From brain. 35 chromosomes. 



FIG. 8. From female gonad. 36 chromosomes. 



FIG. 9. From neural tube. 35 chromosomes. 



