Subclass
Theria (Therians)
Phocoena phocoena. Photo: (c) Ecomare/Salko de Wolf, some rights reserved (CC BY-SA)
Theria (/ˈθɪəriə/; Greek: θηρίον theríon, wild beast) is a subclass of mammals amongst the Theriiformes (the sister taxon to Yinotheria). Theria includes the eutherians (including the placental mammals) and the metatherians (including the marsupials).