neritid vs nerita

neritid and nerita both are nouns.

Word	Noun	Adjective	Verb	Adverb
neritid	Yes	No	No	No
nerita	Yes	No	No	No

As nouns, nerita is a hyponym of neritid; that is, nerita is a word with a more specific, narrower meaning than neritid:

neritid: operculate seasnail of coastal waters with a short spiral shell
nerita: a neritid gastropod having a short smooth or spirally ridged shell with thick usually toothed outer lip and toothed operculum

Other hyponyms of neritid include bleeding tooth, Nerita peloronta, neritina.

neritid (noun)	nerita (noun)
operculate seasnail of coastal waters with a short spiral shell	a neritid gastropod having a short smooth or spirally ridged shell with thick usually toothed outer lip and toothed operculum