nerita vs neritid

nerita and neritid both are nouns.

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

As nouns, neritid is a hypernym of nerita; that is, neritid is a word with a broader meaning than nerita:

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

Other hypernyms of nerita include neritid gastropod.

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