The Dependence of Pigment Granule Migration on the Cortical Reaction in the Eggs of Arbacia Punctulata

The intensely pigmented echinochrome granules (chromatophores) of the Arbacia egg, which are distributed throughout the endoplasm prior to fertilization, migrate to the fertilized surface about 10 minutes after insemination. 2. In partially-fertilized eggs, in which the cortical reaction has been blocked or interrupted, the pigment granules migrate only to fertilized cortex. 3. Fertilized cortex in partially-fertilized eggs can recruit pigment granules not only from its immediately-underlying endoplasm, but also from a considerable distance in endoplasm apparently otherwise unaffected by the cortical reaction.