A first edition of Charles Darwin's seminal book "On the Origin of Species" will be sold this week, after it was found in a family's toilet in southern Britain, an auction house says.<br/>The book, which was first printed in 1859, was bought by a family for just a few shillings in a shop about 40 years ago, Christie's auction house says. The family has since kept the work on a bookcase in the guest toilet at their home in the Oxford area. <br/>The book will go under the hammer in London on Tuesday, to coincide with the 150th anniversary of the publication of the father of the theory of evolution's famous work. The book, one of about 1,250 copies in the first print run, is expected to fetch dollar 108,277.<br/>