354 ORILLA STOTLER WERNER. 



PLATE i . 



FIGS, i to 6. Cells from the amnion of males of the Indian runner duck. 

 The Z or sex-chromosome is numbered 38Z in each of the cells. 76 chromosomes 

 present. 



FIG. i. Late prophase. The large chromosomes are shown in the character- 

 istic peripheral position with the smaller ones within the circle. 



FIG. 2. An earlier prophase than i. 



FIGS. 3, 5, 6. Cells in metaphase. The stippled line in each case indicates a 

 possible grouping of the chromosomes in maternal and paternal groups. This 

 grouping in each case has been considered with especial reference to the 12 largest 

 chromosomes. The autosomes paired from 37 to 33, according to size. 



FIG. 4. An early metaphase. Autosomes paired from 37 to 23. 



