This paper analyzes Hugolinus of Orvieto’s treatise on the perfection of species, which was written around 1348-1349, and compares Hugolinus’s main theses with the positions of other theologians of the same period. The first part of the paper examines the main concepts (nobility, latitude, degree) that Hugolinus uses to present his conclusions. Then, the views of Hugolinus on the order of perfections and the way to measure them are studied in comparison with previous approaches to the same problem (in particular those of John of Mirecourt and Peter of Ceffons). The final part of the paper indicates how the weaknesses of Hugolinus’s positions explain to a certain extent the theories that John of Ripa and Jacques Legrand will develop concerning the problem of specific perfections.