[Study on the pineal gland of ungulates]

Study of the pineal gland of 91 Ungulates belonging to 55 species shows the constant presence of calcarine concretions of various importance. These concretions develop in the walls of vessels that first undergo a preliminary transformation characterized by the presence of alcian blue or PAS positive substances. In nearly all cases, the presence of alcian blue positive cells with processes (distinct from mastocytes) can be found in the pineal gland of ungulates. These elements sometimes contain fine calcarine granulations that probably are the site of origin of acervuli. These observations were extended to several marsupials, carnivora, pinnipeda and perissodactyles.