<Li> Trematodes are released from the definitive host as eggs, which have evolved to withstand the harsh environment </Li> <Li> Released from the egg is the miracidium . This infects the first intermediate host in one of two ways, either active or passive transmission . a) Active transmission has adapted for dispersal in space as a free swimming ciliated miricidium with adaptations for recognising and penetrating the first intermediate host . b) Passive transmission has adapted for dispersal in time and infects the first intermediate host contained within the egg . </Li> <Li> The sporocyst forms inside the snail first intermediate host and feeds through diffusion across the tegument </Li> <Li> The rediae also forms inside the snail first intermediate host and feeds through a developed pharynx . Either the rediae or the sporocyst develops into the cercariae through polyembrony in the snail . </Li>

Three points of difference between trematoda and cestoda