- monotreme, egg-laying mammal - the most primitive mammals comprising the only extant members of the subclass Prototheria
--1 is a kind of prototherian
--1 has particulars:echidna, spiny anteater, anteater; echidna, spiny anteater, anteater; platypus, duckbill, duckbilled platypus, duck-billed platypus, Ornithorhynchus anatinus