The manuscript Atlas de Historia Natural, known as the Pomar Codex, in the University Library of Valencia contains more than a hundred images that are practically identical to those found in the Tavole acquerellate in the collection of Ulisse Aldrovandi in the University Library of Bologna. I will argue that the overwhelming presence of images belonging to Ulisse Aldrovandi's collection in the Pomar Codex indicates that future research on this text should be based on trying to understand possible methods of exchange between Italy and the Iberian Peninsula. This case study will enable us to better understand the mechanisms of communication and exchange among early modem members of the Republic of Letters.