class Polyplacophora vs genus Chiton

class Polyplacophora and genus Chiton both are nouns.

Word	Noun	Adjective	Verb	Adverb
class Polyplacophora	Yes	No	No	No
genus Chiton	Yes	No	No	No

class Polyplacophora (noun)	genus Chiton (noun)
small class of marine mollusks comprising the chitons; sometimes considered an order of the subclass Amphineura	a genus of Polyplacophora