Limpet

Limpet: A variety of salt water and fresh water snails.

O spendid idea ... though did you notice those things whirling part the window a moment ago?
Yeah, the leaves?
No, they were limpets...

A Book for Today: The Bone People by Keri Hulme

Where the gold harvest was ready the peasants in their hats like limpets winnowed the rice against little curved shelters of plaited bamboo.