Meaning of EGG-LAYING MAMMAL

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