82 



J. Thos. Patterson. 



contour of the overlying cells. This is especially clear in the 

 photograph at the point marked x as well as in other parts of the 

 blastoderm. Hence, if it were possible to view this section in the 

 living condition, the subgerminal cavity would be seen to contain few 

 or no nucleated cells; for all these cells would then be crowded up 



Fig. VII. A diagrammatic reconstruction of a blastoderm taken thirty- 

 one hours after fertilization. It is farther advanced than the majority of 

 eggs at this time. Numbers 1, 2, 3, etc., represent the regions of the blas- 

 toderm which are one, two, three, etc., cells deep, respectively. The broken 

 line around "1" indicates the region where the depth is approximately one 

 cell. The plane of the section for Fig. 30 is slightly to the left of line CD. 

 X 27.2. 



against the under surface of the blastoderm. Their present position 

 within the cavity shows that they have loosened and sunk down 

 during fixation. There would be, however, in the living condition, 

 a few large non-nucleated yolk masses (m), as the present position 

 of these bodies indicates that they have arisen out of the yolk iying 

 beneath the floor of the cavity. 



