Ornately marked and brightly colored snails of brackish waters

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Neritina \Ner`i*ti"na\, prop. n. (Zo["o]l.) A genus including numerous species of shells resembling Nerita in form. They mostly inhabit brackish water, and are often delicately tinted.

Wikipedia Word definitions in Wikipedia
Neritina is a genus of small aquatic snails with an operculum , marine , brackish water , and sometimes freshwater gastropod mollusks in the family Neritidae , the nerites. Neritina is the type genus of the tribe Neritinini.

WordNet Word definitions in WordNet
n. ornately marked and brightly colored snails of brackish waters