Sunday, February 3, 2008

Suck rocks.

No, they're called suck-rocks.

Back to Bermuda for a walk on the beach. The tide is low enough to reveal a cluster of chitons, Chiton tuberculatus, hunkered down on the wave-scoured limestone. The largest one is about 2.5 inches long. They are algae-eating marine mollusks of the class Polyplacophora, which refers to the many (in this case, eight) valves. This partial segmentation allows them a certain amount of flexibility, making it possible to snug down tightly onto an irregular surface, clinging with the fleshy, gasket-like foot. If pried off, not easily done, they curl up like armadillos. Armadillos? They curl up like pill bugs. Pill bugs? They curl up like chitons. But the fact is that armadillos are the designated reference animal for curling up in a ball.

Chitons move around a bit at night, but usually return to their favourite dimple before dawn to ride out the tides of the following day.

Chitons are also called sea-cradles, from a time when there were such things as cradles, and in Bermuda, because of what they do most of the time, suck-rocks. So guess which was the first name that came to mind when I was interviewing for a biology teaching job and was asked to identify a random assortment of natural history specimens. One was a jar of chitons.

"Suck-rocks," I said.

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