Selachii vs subclass Selachii

Selachii and subclass Selachii both are nouns.

Word	Noun	Adjective	Verb	Adverb
Selachii	Yes	No	No	No
subclass Selachii	Yes	No	No	No

As nouns, Selachii and subclass Selachii are synonyms defined as:

Other synonyms of Selachii include Elasmobranchii, subclass Elasmobranchii.

Selachii (noun)	subclass Selachii (noun)
sharks, rays, dogfishes, skates	sharks, rays, dogfishes, skates