1. Oogenesis 2. From oocyte to zygote 3. Does cleavage cut up a preformed spatial pattern? 4. The limits of mosaicism in non-spiralian cleavage 5. Cellular interations in the morula and blastula: the case of sea urchin embryos 6. Interactions at morula and blastula in other embryos 7. Interactions between moving cells: the case of amphibian gastrulae 8. Spatial determination in the gastrulae of other groups 9. Determination in embryos showing partial cleavage 10. Patterns and mechanisms in early spatial determination References Index.
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