Effects of temperature on the migration of primordial germ cells in the chick embryo.

1. Incubating eggs at reduced temperatures leads to a decline in the rate of embryonic development. 2. All tissues do not respond equally and the migration of primordial germ cells is delayed in time, but occurs at an earlier stage of development than for normally incubated eggs. 3. The results are interpreted in relation to the integrated development of the gonad.