Experts say about 1,250 copies of Charles Darwin's On the Origin of Species were published in its first edition. (Lucas Jackson/Reuters)A rare, first-edition copy of Charles Darwin's On the Origin of Species fetched a hefty price at a London auction Tuesday, after having been kept in a British family's guest washroom for years.

Auction house Christie's sold the influential, green-cloth volume for £103,250 (about $174,000 Cdn), including buyer's premium.

An anonymous telephone bidder purchased the book on the 150th anniversary of the work's original publication. It is Darwin's seminal book that shared his theory of evolution with a lay audience.

"It's actually rather ordinary looking, but when you think about the importance of this and how it really revolutionized our understanding of all of the life sciences and how life itself fits together, it’s really amazing," explained Margaret Ford, head of the Christie's London book and manuscript department.

Experts say the initial 1859 print run of On the Origin of Species included about 1,250 copies.

Offered as part of Christie's valuable manuscripts and printed books sale, the gilt-decorated tome had been estimated to fetch up to £60,000 (about $100,000 Cdn)

The seller's family bought the volume about 40 to 50 years ago for "a few shillings," Christie's officials said.

The son-in-law of the seller recently visited a Darwin exhibit which had an On the Origin of Species first edition on display. He realized it was the same as the one his in-laws had been keeping in the guest washroom of their home, near Oxford, and the book was promptly put up for sale.

First editions of the work have periodically made appearances at auction, including another copy that also sold in London earlier this year for nearly $60,000.