Abstract

A model is given of the development of a radialised larval head pattern inLimnaea stagnalis, as it occurs under certain experimental conditions. It is assumed that the differentiation of the pattern is entirely based on cell-internal factors, and that the internal state of each cell is dependent on that of its progenitor and on the direction of the division by which it is produced. This internal state determines the direction of the subsequent division or the nature of the cell's differentiation. Cell interactions, which are during this period of minor importance, are left out of consideration