The germ-cells. 



655 



left. With the final sections of this row the sub-germinal mass of 

 yolk-laden cells has almost disappeared, but within the embryo there 

 is one of these germ-cells in an unusual position under the epiblast. 

 In the 5th row of sections there are none actually within the 

 embryonic foundation, but there is one germ-cell at the base of the 

 germinal path to the left, and several others between epiblast and 

 mesoblast on the blastoderm. In addition, several germ-cells of the 

 larger size lie between epiblast and hypoblast of the blastoderm beyond 

 the region of extension of the mesoblast. Much the same conditions 

 prevail along the whole row of sections. 



y- ^'V 



E H F G D C B 

 Fiiî. B. 



A 



In the 6th row of sections the embryonic foundation (text-figure B) 

 is rapidly flattening, i. e., the hinder end is approaching. There are 

 still many of the cells in question on the blastoderm between the yolk 

 and the mesoblast, that is to say, at the commencement of the ger- 

 minal path. At the end of the row there are some on the blastoderm 

 at the top of the yolk, but their number is not large, and none of 

 them lie between the yolk and the mesoblast. No part of the latter 

 is now segmented. The conditions in this row are depicted in text- 

 figure B. All the cells to the right except one are lettered and de- 

 picted under high magnification in Fig. 52 A — H, Plate 44. None 

 of them lie within the parts of the embryo, and only one {A) is within 

 the mesoblast. J., B^ C, and D are of the average size 0.036 mm, 

 that is, they have still two divisions to undergo to bring them down 

 to the normal size of germ-cells. E, JP, (r, and H, on the other 

 hand , resemble normal germ-cells not only in all their other 

 characters, but also in size. From their relative positions, as shown 



