Carlo Fornasini (1854-1931) was an eminent Italian micropaleontologist who left his extensive collection of foraminifera to the Giovanni Capellini Geological Museum of the University of Bologna (Capellini Museum) between the late 19th century and the early decades of the 20th century. This collection, largely stored in the museum’s repository, has never been studied. In order to assess its content and preservation, an analysis of the collection was conducted. Moreover, unilocular hyaline foraminifera, which Fornasini had dedicated several researches in his long career, were selected and studied. These analyses revealed that out of the over 500 micropaleontological preparations labeled by Fornasini (mainly from Italian Pliocene sediments), 74 are empty, and many holotypes of the 69 taxa he described are missing. Regarding the unilocular hyaline foraminifera described by Fornasini, two holotypes were rediscovered (Fissurina sacculus and Hyalinonetrion clavatum var. exilis), while four neotypes were selected from his samples (Fissurina bradyana, Fissurina calostoma, Parafissurina felsinea, Parafissurina triaculeata). A comparison between the type figures and the specimens in the collection revealed that Lagenosolenia seguenziana, reported by Fornasini as a “new name” for Fissurina marginata Seguenza, should be considered a new species, and a neotype was chosen for it. Unfortunately, it was not possible to select neotypes for the other three species of unilocular hyaline foraminifera described by Fornasini (Fissurina acutissima, Fissurina bicarinata var. placentina, and Fissurina compresso-marginata). Overall, from Fornasini’s material, a total of 52 taxa of unilocular hyaline foraminifera were recognized and illustrated, revealing a variety of species previously unobserved in the Mediterranean Pliocene, at least to the best of our knowledge. Finally, a new species, Lagena catii, was described and dedicated to the colleague who, between the 1950s and 1970s, did more than anyone else to preserve the collection.