ETUDE ONTOGENETIQUE DE L'ORGANE SENSORIEL DU MUSCLE CRUCIFORME DES TELLINACEA

The closed cruciform muscle sense organ of Donax trunculus hasa similar origin to the open one of Scrobicularia plana. Bothdifferentiate as ectodermal pits before the cruciform muscleitself, which is issued from their wall. The sense organ ofDonax is closed immediately after the invagination of the pitand its closure is independent of the differentiation of theventral expansion which characterizes the closed sense organand of the canal which characterizes the open one. (Received 8 August 1983;