A graphical model for evaluating the use of the egg ratio for measuring birth and death rates.

1. A graphical model is described with which one can calculate for any reproductive schedule values for population growth rate, birth rate, death rate, egg ratio, and age structure. Variations are discussed to describe different kinds of life history. 2. Examples are described to show how various population parameters are interrelated and how they vary with reproductive schedule. Discrepancies that arise in deriving instantaneous coefficients from counts of a population growing by discrete steps are noted.