The chromosomes of Biomphalaria tenagophila (Gastropoda--Basommatophora--Planorbidae).

The subfamilies Bulininae and Biomphalariinae are of medical importance being potential intermediate hosts of human and herbivore schistosomiasis. South America is inhabited by the subfamilie Biomphalariinae. Biomphalaria glabrata (=Australorbis glabratus) is the principal host of Schis tosoma mansoni in Brazil. In Argentina there are no cases of schistosomiasis as yet although Biomphalaria tenagophila, of extensive distribution in this country, has proved to be also host (Rey 1956). Previously eight papers were devoted to the cytogenetics of the subfamily Biomphalariinae (Rangel 1951, Fraga and Goncalves 1956, Burch 1960 a, b, 1965, Natarajan et al. 1965, Narang 1974, Raghunathan 1976) but, excepting in the papers of Narang (1974) and Raghunathan (1976), karyotypes have not been shown. The aim of this research is to report the study of the meiotic and mitotic chromosomes of three populations of Biomphalaria tenagophila.