Determinação do período de desenvolvimento e da viabilidade das desovas de duas populações de Biomphalaria glabrata e Biomphalaria tenagophila (Mollusca, Planorbidae)

Oviposition of populations of B. glabrata and of B. tenagophila were studied comparatively. TJnder the experimental conãitions significant difjerences were óbserved in the áevelopmental period of the eggs. The probabüity of hatching in relation to the number of days required for the development of the eggs followed a Poisson distribution as shown in graph. 2.