ABSTRACT
The technique of marking the unincubated duck blastoderm with fine particles of Chinese ink leads to the following conclusions:
there exist superficial morphogenetic movements during the first few hours of incubation;
surface material rolls round the posterior, lateral, and anterior margins;
there is a direct continuity between extra-embryonic and embryonic endoblast.
The endoblastic layer forms therefore by surface material rolling round the posterior, lateral, and anterior margins.
Copyright © 1955 by Company of Biologists
1955
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