Here is a link for you to read about the Hemingway Cats...I am posting part of the article here.
http://cats.about.com/od/felinegenet...polydactyl.htm
Oh and the extra toes I think are actually a fault, not a valued quality.
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Many-Toed Polydactyl Cats
Ernest Hemingway was an amazing man, with many talents and interests. He was also an inveterate cat-lover, because he admired the spirit and independence of cats. Hemingway acquired his first cat from a ship's captain in Key West, Florida, where he made his home for a number of years. This cat, which may have been a Maine Coon, had extra toes (technically known as polydactyl, latin for "many digits"). Today, approximately 60 cats, half of them polydactyl, make their home in the Ernest Hemingway Museum and Home, in Key West, protected by the terms of his will. At least some of those cats are descendents of Hemingway's first cat, and are given fanciful names, as he once did, after movie stars and even characters in his book. The cats of the Hemingway Museum are so popular and so well-known, that the nickname "Hemingway Cats" has often been given to polydactyls.