Resumen de Sobre la presencia de dos cercarias en el ovario de almeja (Tapes aureus Gmelin) en la bahía de Santander
The presence of two species of cercaria in the visceral mass of Tapes aureus, the most abundant shellfish of the bay of Santander (N. Spain), is reported. Bucephalopsis haimeana (Lac.-Duth.) was found in animals collected in May, but was absent in those collected in March and June. The dimensions of the cercaria are slightly greater than those given for Mediterranean specimens. Cercaria ophiocerca Palombi was, in general, more frequent that Bucephalopsis, and was found in specimens collected in May and June. In March was found to be absent. The observations in Naples range from September to December. This cercaria is new to spanish fauna, and probably also the first record for the Atlantic. The development of both cercaria falls in the period of the first stage of sexual ripening of Tapes aureus, and determines frequently the parasitary castration of the shellfish.
