A giant scale worm sits on the Antarctic seabed at 2,116 feet (645 meters) deep.

At 10 inches (250 millimeters) long and weighing 11 ounces (300 grams), the worm is an example of a phenomenon called ''gigantism,'' which scientists still do not fully understand.

''Gigantism is very common in Antarctic waters,'' Martin Riddle said in a statement released February 19, 2008. The Australian Antarctic Division scientist led the recent expedition that photographed this worm and other animals.

''We have collected huge worms, giant crustaceans, and sea spiders the size of dinner plates.''

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