Movie 3.

Vegetal view of a Hofstenia embryo with 1a and 1b blastomeres labeled with fluorescein dextran. Time-lapse recording of a 4-cell embryo viewed from the vegetal pole after both 1a and 1b micromeres were injected with fluorescein dextran. Labeled daughter cells can be seen moving towards the vegetal pole, internalizing the macromeres in the process.