Owing to the comparative rarity of Paramphistomes in Britain the difficulties of attempting to work out the life cycle are very great. Upto the present the problem has been approached from two angles; firstly, where an infected animal has been found at the abattoir, and finally traced back to its farm of origin, extensive collection of snails has been carried out at the assumed site of infestation ; secondly, where it has been possible to collect large numbers of adult worms from slaughtered animals, these have been picked out of the rumen and placed in dishes containing boiled tap water for several hours, in which medium oviposition takes place rapidly. These eggs have been collected and cultured, and laboratory-bred snails have been exposed to the miracidia, but so far no infection has taken place. This has of necessity been sporadic and no concentrated systematic attempts at infection over long periods have been possible.