The relation of phenotype to habitat in an introduced colony of Cepaea nemoralis.

The introduced colony of Cepaea nemoralis at Lynchburg, Virginia, contains only yellow shells. The population respond to the characteristics of the environment by adjusting the frequencies of the banding morphs and by regulating the amount of fusion of adjacent bands. In this respect they fulfill a prediction based on the observations of Clarke (1960) on British colonies of Cepaea hortensis.