sentence1: Scurria plana is a species of sea snail , a true limpet , a marine gastropod mollusc in the Lottiidae family , one of the families of the true limpets .
sentence2: Scurria plana is a species of sea snail , a true limpet , a true gastropod mollusc in the Lottiidae family , one of the families of the marine limpets .