Sailing to auction this fall is a 7-inch-long whale’s tooth decorated by private James Bute of the Royal Marines while aboard the ship from which Charles Darwin surveyed the Galapagos Islands in 1835.

Darwin made significant scientific observations from the H.M.S Beagle which formed the basis of his seminal work, “The Origin of Species.”

The hand-engraved ivory depicts the three-masted sloop H.M.S. Beagle slicing through rough waters against a mountain backdrop. With a high estimate of 50,000 pounds, the carved tooth will be auctioned by Bonhams in London on Sept. 16.

Known as scrimshaw, this sailor-made art form was created during idle moments at sea or port.

In Darwin's account "Voyage of the Beagle," the budding scientist wrote that the five-year, round-the-world Beagle trip was "by far the most important event in my life." Specimens culled from the Galapagos Islands, off Ecuador, came to shape his theory of evolution.

In an e-mailed statement to Bloomberg, Jon Baddeley, head of Bonham’s collectors’ items, wrote, “This is without doubt the most important British scrimshaw to come on the market in my 30-year career."

The year 2009 is the bicentenary of Darwin’s birth and marks 150 years since the publication of ‘The Origin of Species.’