1. Of or belonging to the infraclass Eutheria, a division of mammals to which all the placental mammals belong.
真哺乳亚纲的关于或属于哺乳动物真兽亚纲的一个下纲，包括有胎盘哺乳动物
2. Of or belong ing to the infraclass Eutheria, a division of mammals to which all the placental mammals belong.
真哺乳亚纲的关于或属于哺乳动物真兽亚纲的一个下纲，包括有胎盘哺乳动物