The problem of sea urchin egg fertilization and its implications for biological studies.

The analysis of sea urchin egg fertilization shows that several phenomena common to other biological systems are involved: cell recognition, cell fusion, exocytosis and initiation of mitotic activity. Both the role of calcium ions in cell fusion and exocytosis and the function of the cell surface in the initiation of mitotic activity appear to have general applicability. The study of fertilization can contribute to the elucidation of these processes and, reciprocally, progress in this field can help to advance our understanding of the mechanisms of fertilization in sea urchins and other organisms.