PLATE 7 
EXPLANATION OF FIGURES 
Mostly blastocysts with entoderm mother cells. 
1 Portion of 13th section through ovum No. 50 (5), showing its only entoderm 
mother cell; total 21 sections; 65 cells; Bouin; 5u. XX 500. 
2 Portion of 13th section through ovum No. 88 (17), taken as indicated by 
parallel lines on fig. 18, pl. 16; characteristic entoderm mother cell is shown; 
total 18 sections; 103 cells, of which 6 are entoderm mother cells; Hill’s fluid; 
Su. X 500. 
3 Section through 6 of the 9 entoderm mother cells of ovum No. 50 (4); 16th 
section (total 20 sections); 67 cells; Hill’s fluid; 5u. X 200. 
4 The 15th section through ovum No. 88 (16), of which the 11th section is 
shown in fig. 11, pl. 16; total 20 sections; large entoderm mother cell is shown in 
blastocysts wall; 82 cells, including 10 entoderm mother cells; Bouin; 5u. X 500. 
5 23-celled incomplete blastocyst No. 173’ (7); 13th of a total of 23 sections; 
aceto-osmic-bichromate; 5u. * 200. 
6 The 12th section through ovum No. 88 (3), showing several entoderm 
mother cells and much yolk and coagulum; 23 sections in series; 69 cells, of which 
10 are entoderm mother cells; Bouin; 5u. X 500. 
110 
