Different phenotypic variation of the snails Cepaea nemoralis and C. hortensis in a ‘mixed’ population in Southern Sweden

Attention is drawn to the sympatric occurrence, in a small area in southern Sweden, of a population of Cepaea hortensis and one of C. nemoralis which show a striking difference in their phenotypic variation. The relative frequencies of the various morphs present in each population are reported. After a discussion of some possible explanations of the different variation patterns, the importance of additional records of such singular “mixed” populations of these species of snails is emphasized.