74 



T. H. MORGAN. 



shows a somewhat similar condition, where, however, the lighter 

 material of the top of the egg has sunken into the interior. This 

 was due to the eggs being placed on the paper in an inverted 

 position while in the two-cell stage. The figures show that the 

 smallest cells are in the interior of the egg, and not on the sur- 

 face of the black hemisphere. 



In order to meet the possible objection that the egg may absorb 

 water from the small, slightly damp, piece of paper, another series 



FIGS. 7-12. Eggs developing out of water. 



of experiments was carried ou't, in which the eggs, deprived of 

 their outer coats, were kept on pieces of glass. For several min- 

 utes the eggs were left on the glass exposed to the air, in order 

 that the water sticking to their outer coats, or to the glass, might 

 dry off. They were then placed in the moist chamber. An egg 

 that had reached a late blastula stage under these conditions is 



