egg-laying mammal(n = noun.animal) monotreme - the most primitive mammals comprising the only extant members of the subclass Prototheria;
is a kind of prototherian
has particulars: anteater, echidna, spiny anteater, anteater, echidna, spiny anteater, duck-billed platypus, duckbill, duckbilled platypus, ornithorhynchus anatinus, platypus

aquatic mammal, artiodactyl mammal, cetacean mammal, digitigrade mammal, eutherian mammal, female mammal, fissiped mammal, fossorial mammal, gnawing mammal, hoofed mammal, leporid mammal, mammal, mammal family, mammal genus, mammal semnopithecus, megatherian mammal, musteline mammal, perissodactyl mammal, pinniped mammal, placental mammal, plantigrade mammal, pouched mammal, sirenian mammal, unguiculate mammal, viverrine mammal, young mammal