acorn barnacle

British  

noun

1. any of various barnacles, such as Balanus balanoides, that live attached to rocks and have a volcano-shaped shell from the top of which protrude feathery food-catching appendages (cirri)

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Example Sentences

That’s because a thatched barnacle is considered to be as different from an acorn barnacle as it is from the seagrass.

From Nature

“I was looking at photographs of these really interesting underwater specimens, like acorn barnacles and other corals,” he said before the show.

From Washington Post