Quick Quiz: Nouns Score: Change category, Flip order Reset Incorrect! Try again. Noun: oligochaeta Your choice? earthworms a mineral consisting of magnesium iron silicate; a source of magnesium extinct tiny nocturnal lower primates that fed on fruit and insects; abundant in North America and Europe 30 to 50 million years ago; probably gave rise to the tarsiers; some authorities consider them ancestral to anthropoids but others consider them only cousins orchid of South America and Trinidad having large yellow and reddish-brown flowers; sometimes placed in genus Oncidium   (Noun: oncidium papilio)