prototherian /ˌprəʊtəʊˈθɪərɪən/

→ compare eutherian, metatherian

• 1. 

  ADJ of, relating to, or belonging to the Prototheria, a subclass of mammals that includes the monotremes 原兽亚纲的

• 2. 

  N any prototherian mammal; a monotreme 原兽亚纲哺乳动物