Meaning of EGG-LAYING MAMMAL

WordNet Dictionary
	Definition:		[n]  the most primitive mammals comprising the only extant members of the subclass Prototheria
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	Synonyms:		monotreme
	See Also:		anteater, duckbill, duckbilled platypus, duck-billed platypus, echidna, Ornithorhynchus anatinus, platypus, prototherian, spiny anteater