IQ2 MARGARETE REED. 



these figures have the appearance of being pushed or crowded 

 into the interior, that is, the portion of the cell which comes to 

 the surface is quite small compared with the size of the cell 

 which lies mainly within the egg. 



This appearance of the cells seems to be caused by the di- 

 vision planes coming in more or less obliquely so as to cut off 

 one cell with a small surface area as No. 9, Fig. I . At the next 

 cleavage, the division of this cell would give rise to one cell en- 

 tirely within the egg and one coming to the surface. Cell 27, 

 Fig. 3, shows the beginning of such a division while cell 70 or 

 71, Fig. 10, may have been formed in this manner. The follow- 

 ing division of such a cell would then form cells lying entirely 

 within the egg. 



So far as I have been able to trace, the yolk cells also show no 

 cutting off of interior cells during the early cleavage stages. 

 Such a cell as 72 in Fig. 4, is but the end of a cell which other 

 sections show coming to the surface. 



These observations show that there is no delamination division 

 cutting off a number of cells parallel to the surface but that the 

 first formed cells of the interior are produced by the same division 

 planes as are the cells of the surface and by their subsequent 

 division form the cells of the interior. 



COLUMBIA UNIVERSITY, 

 December 13, 1904. 



