Frederick Adams Woods 



315 



also used for a count; there were 710 germ-cells and all were in the 

 genital glands. 

 M;V''::, V>.j, > ; uV The following table shows the proportionate dis- 



tribution of primitive ova from the time when they 

 could first be distinguished up to the complete forma- 

 tion of the genital gland at about the time of sexual 

 differentiation into male and female. 



■'\ Fig. 12 



Fig. 14 



Fig. 13. Cross-section through the gut region of an embryo of 11.5 mm. En. 

 €ndoderm, Ur. germ-cells. Harvard Embryological Collection. Trans. Series 306. 



Fig. 13. Ventral portion of an embryo of 15 mm. En. endoderm, Ur. germ-cells. 

 Harvard Embryological Collection. Trans. Series 499, Section 337. x 38. 



Fig. 14. Ventral portion of an embryo of 19 mm. En. endoderm, Ur. germ-cells 

 in the genital gland. Harvard Embryological Collection. Trans. Series 137, section 

 390. X 38. 



Mode of Migration. 



There is no question but what these cells migrate with reference 

 to the embryo as a whole since the number ventral to the mesen- 



1 One side onlv counted. 



Part of series lacking. 



