Viene confermata la presenza, segnalata da Walcott et. al., nel capo dei piccioni viaggiatori, di una serie di strutture da lui identificate come magnetite, alle quali si dovrebbe attribuire la sensitività di questi animali al campo magnetico e alle sue variazioni naturali. Vengono portate evidenze isto-topografiche di tre forme di sensori: particelle sparse, ammassi e infine di nuclei di eritrociti ricoperti dalle stesse.
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Con il contributo del Ministero per i Beni e le Attività Culturali