Christie's auction house in New York is auctioning off a skull, which is believed to have been used as a ballot box by the society's members around 1872. The skull has a hinge on top and is surrounded by crossbones, according to the Associated Press.
The book is inscribed, Edward T. Owen. 1872. on one side and 322. on the other. The inscription on the right cross bone, Thor, "could be a name which would have been assigned to a member upon induction," according to Christie's.
The winning bidder will get something that could be more valuable than the skull. He or she will also get a black book with names and pictures of earlier members.
Christie's believes the skull and book will go for somewhere between $10,000 to $20,000 when it goes up for auction Jan. 22.
The auction house has agreed to keep the seller's name a secret, describing the person only as a European art collector.