Notes on the development of metacercaria and adult of Echinostoma porteri Fashuyi (Echinostomatidae).

The metacercaria of E. porteri was found to retain its viability for a longer time in Bulinus (Physopsis) globosus (Morelet) than in Bulinus (Bulinus) forskalii (Ehrenberg) and Lymnaea natalensis (Krauss) which is the natural host for other larval stages. It becomes infective to definitive hosts about 6 h after commencement of encystment and loses its viability after 14 days in the snail host. Development of adult takes place experimentally in chicks, pigeons and rats, but hosts show age resistance to infection. Growth of adult worm is most rapid between 4th and 6th day and declines after the 17th day. Proportionate increase in body length is higher than similar increases in size of other parts of the body.