PLATE 3 



EXPLANATION OF FIGURES 



20 Prophase from stomach (region 6) showing eighteen chromosomes in 

 three groups. The middle group shows clearly the early splitting of two of four 

 chromosomes, A and B. The size difference indicates that the division has just 

 taken place and the chromosomes have not had a chance to grow to normal size. 



21 a, b, c, d Normal somatic metaphase complexes. Figure 21 a metaphase 

 group from stomach epithelium showing size of chromosomes in the 'normal' 

 gut cell. Figure 21 b, c and d, groups from nerve tissue showing typical group- 

 ing found in all somatic tissues. 



22 Metaphase group from stomach (region 6). x, y and .~ represent three 

 sections of the same cell. When superimposed, the group is found to contain 36 

 chromosomes. 



23 Metaphase group from ileum f region 4). Y and Z are two sections of the 

 same cell. The number in this group is probably 72, although there appear to 

 be but 68 chromosomes. 



24 Metaphase, showing 24 chromosomes — from Dr. Stevens' slide — region 

 undetermined. 



25 Metaphase from ileum (region 3)- — 24 chromosomes. Three in center of 

 group show splits. 



26 Metaphase from stomach (region 6) showing 36 chromosomes, grouped in 

 three groups of 12 each. 



624 



