RECORDS. 



373 



^ 



B 



I 



I 



Fig. I. — Development of entire eggs and of isolated blastomeres of two-cell 

 stage. A, Dentalium ; at the left, development of the whole egg ; at the right, 

 development of the isolated first two cells, producing two defective larva. B, 

 Aviphioxus ; the corresponding experiment, isolated cells producing two perfect 

 dwarfs. 



