Opihi

Limpet is a very inexact term: it is a word that is commonly applied to a wide variety of different snails (from either marine or freshwater habitats) which have a simple shell which is more or less conical in shape, and which is either not coiled, or appears not to be coiled, in the adult snail. Most marine limpets have gills, whereas freshwater limpets and a few marine limpets breathe air; all these various kinds are only very distantly related. In other words, the name limpet can be used to describe various unrelated groups of gastropods which have independently evolved a shell of the same basic shape.
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