LONDON - British marine experts have found what they claim is a world first -- a six-legged octopus, or "hexapus," whom they have christened Henry.

The unique sea creature, which has two limbs fewer than a normal octopus, is believed to be the result of a birth defect rather than an accident, say his keepers at the Blackpool Sea Life Centre in northwest England.

"We've scoured the Internet and talked to lots of other aquariums and no-one has ever heard of another case of a six-legged octopus," said supervisor Carey Duckhouse.

Henry was discovered in a lobster pot off the north Wales coast two weeks ago, and was one of eight creatures that Sea Life staff picked up from a local marine zoo there -- where staff hadn't noticed his missing legs.

It was only when he attached himself to the inside of a glass tank that Sea Life staff noticed he was two limbs short of a full set. Octopuses are renowned for having three hearts and blue blood, but not usually six legs.

"He's a lovely little thing," said a spokeswoman, adding that he will go on display to the public later this month.