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Marine Biology

Square Peg or Round Whole?
A jellyfish's changing shape surprises a scientist

In Greek mythology, the gods transformed the ocean nymph Clytia into a flower. Until recently no one realized her namesake, the jellyfish Clytia languidum, could also change form. But marine biologist Edith Widder of Florida's Harbor Branch Oceanographic Institution has discovered that the little jelly transforms when touched.

Widder collected the shape-shifter, barely an inch (about two centimeters) in diameter, about 2,800 feet (850 meters) deep off the Bahamas using the Johnson-Sea-Link I submersible. In her lab Clytia's round transparent body revealed a lavender central stomach with four radial canals, each containing a white reproductive organ.

"When I touched its body, it changed into a square," she says. "This is really unusual for a jellyfish. I've only seen it once before." After she turned off the lab lights, the square glowed green with bioluminescent light. Widder is still working out why Clytia does this. "Perhaps the change acts like a skull and crossbones, a warning to predators such as fish or sea turtles," Widder says, "'Don't eat me or I'll sting you.'"

—John L. Eliot

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