[The life cycl of Maritrema pyrenaica Deblock et Combes, 1965, a parasite of insectivorous micromammals in the Pyrences (author's transl)].

The life cycle of Maritrema pyrenaica is described. M. pyrenaica develops to the sporocyst stage in the snail Bythinella reyniesii. The xiphidio-cercaria, monostomous, anenterous in type, is liberated in water and actively penetrates a Crustacea Gammarus pulex where it encysts. From the point of view of epidemiology, the focuses of M. pyrenaica are divided into two different areas: the area where the parasites multiply (that we call "l'endemiotope") coinciding with the Bythinella biotope and the area limited to the length of the river where the Vertebrate is parasitized.