The inheritance of some characters in Cepaea hortensis and Cepaea nemoralis (Gastropoda).

N recent years the remarkable polymorphism of snails of the genus Cepaea IHeld has continued to attract considerable attention. The variation from place to place in the proportions of the different phenotypes has proved to be useful material for the study of evolution in natural populations (CAIN and SHEPPARD 1950, 1954; CLARKE 1960; CLARKE and MURRAY 1962; LAMOTTE 1951, 1959; SCHNETTER 195 1 ; SHEPPARD 195 1 ) . The foundation of such population studies must always be a knowledge of the mode of inheritance of the characters of the polymorphism. Since most of the field work has been carried out with Cepaea nemoralis (L.) , it is natural that relatively more is known of the genetics of this species (LANG 1908, 1911, 1912; LAMOTTE 1951, 1954; CAIN and SHEPPARD 1957; CAIN, KING and SHEPPARD 1960). Recently, however, LAMOTTE (1959) and CLARKE (1960) have discussed the distribution of phenotypes in mixed populations of Cepaea nemoralis and Cepaea hortensis (MULLER). Their work has served to point out that our knowledge of the genetics controlling the polymorphism is meager in C . hortensis. Cepaea hortensis has the distinction of having provided one of the first demonstrations that the laws of Mendelian inheritance apply to animals as well as to plants (but see BATESON and SAUNDERS 1902). LANG (1904) had already begun his pioneering researches on Cepaea at the time of the rediscovery of MENDEL’S experiments, and he pointed out that the inheritance of banding in C . hortensis could be explained in a similar manner. LANG was not the first to undertake the breeding of C . hortensis. There are indications of the mode of inheritance of banding in the work of SEIBERT (1876), who found that banded parents produced only banded offspring, and of BROCKMEIER (1888), who obtained a banded individual from the offspring of an unbanded snail. However, it was LANG who first understood the Mendelian nature of the inheritance. In his first paper on the breeding of hortensis (1904), he established the important points (1) that Cepaea cannot self-fertilize and (2) that sperm from several matings can be stored for long periods without losing its viability. By means of both backcross and F, generations, LANG showed that the unbanded condition (represented symbolically as 00000) is dominant to the five-banded condition (represented as 12345). In only one individual (a 12045)