Abstract
Susceptible snails, confined as "targets" in linear channels, readily became infected when exposed to miracidia of S. mansoni released several feet away. The frequency of infection among targets was, however, markedly reduced when susceptible or various insusceptible snails were interposed as "decoys." These and related findings suggest that insusceptible snails may play a role, hitherto unsuspected, in the epidemiology and control of schistosomiasis. Elements of the experimental system may also prove applicable to the analysis of target-finding by other organisms.