No lights, please!

Last February, among the barnacles I brought home for my intertidal snails, a small chiton was hiding. He joined the other beasties in the aquarium, and trundled about happily for some time, cleaning algae off the glass walls and the stones. Then he disappeared.

Much later, cleaning the aquarium, I found him, inside an old moon snail shell. He'd grown some, was obviously thriving.

Since then, I've seen him often, on the outside of the moon snail shell, sometimes deep inside, sometimes on the bottom. But always on the snail shell; he never explores the glass walls any more, nor the sandy floor, nor even other shells. The moon snail shell is home.

Woody chiton, Mopalia lignosa , on algae-encrusted moon snail shell, fleeing the camera.

Chitons are slow animals, as slow, almost, as limpets. (Although a limpet on a mission can trot right along.) And on the beach, the chitons don't seem to mind being partially out of the water at low tide. I thought that maybe I could get some clear photos of "Woody", and maybe get a close look at his spines with the microscope, if I took his shell out of the tank. I put him in a tray with a half-inch of water, and set up the lights and camera.

But Woody didn't approve. As I rolled the shell around to get him within reach, he kept turning, heading down, towards the bottom of the shell, under the water. There are light-sensitive spots on his plates; he saw those bright LED lights, and hated them. Every photo I took was of him hurrying away. I didn't even try to aim the microscope at him.

He never left the moon snail shell. It's his safe place.

Side view.

The small, soft spines on his girdle arise from light freckles. The girdle is quite flexible; at one point, he galloped up and over the limpet, lifting the edge of the girdle to fit.

I gave up and replaced his home in the tank. He stopped racing around; he must have been pretty tired. He's still on the moon snail shell.