sentence1: Lottia emydia is a species of the sea snail , a true limpet , a marine gastropod mollusk in the Lottiidae family , one of the families of the true limpets .
sentence2: Lottia emydia is a species of sea snail , a true limpet , a marine gastropod mollusk in the family Lottiidae , one of the families of true limpets .