Observations on the dispersal of two species of British land snail

The overnight movements of Candidula intersecta (Poiret) and Cernue1la virgata (Da Costa) were observed in the Cotswolds by releasing marked snails and measuring the distances moved in the subsequent 24 hours. C. virgata moved further than C. intersecta, the maximum distances moved being approximately 300cm and 120cm respectively. C. virgala showed different behaviour depending on the microhabitat in which it was released. The difficulties of interpretation of this kind of study are discussed, particularly those relating to unmonitored environmental factors, condition of the experimental animals and the experimental procedure adopted.