QUEBEC - The new Canadian $50 bill unveiled Monday contains a few changes in addition to the state-of-the-art plastic material introduced as part of Canada's ongoing currency overhaul.

Gone from the new bill are images of human-rights causes, like the women's liberation movement and the UN Declaration on Human Rights. Added is an image of an Arctic icebreaker, the Canadian Coast Guard research ship Amundsen.

Those variations on the back of the bill are to be expected, says the Bank of Canada, because every new currency series carries a different theme.

"The (new) theme is great Canadian accomplishments — in the country, in the world and in space," said spokeswoman Phuong Anh Ho Huu.

Missing from the updated bill are images of the women's rights movement of the early 20th century. They include the Famous Five case, the battle to have women recognized as persons under the 1867 Constitution. Another image that is gone is that of Therese Casgrain, the first female leader of a political party in Canada.

The old bill also contained a quote from the 1948 UN Declaration on Human Rights: "All human beings are born free and equal in dignity and human rights."

Those old images had been included as part of the theme "the Canadian journey," Ho Huu said. She noted they won't disappear overnight because the old $50 will continue to circulate.

"The Famous Five remain an important part of Canadian heritage and will remain in circulation for some time," she said.

Changes to currency are suggested by the Bank of Canada, following a round of public consultation, and subject to the approval of Finance Minister Jim Flaherty.

The front of the new $50 bill continues to carry the image of former prime minister Mackenzie King as well as its familiar reddish hue.

The most obvious change is in the texture of the plastic material, which contains hard-to-counterfeit elements like transparent bits and holograms.

The polymer $50 bill, released several months after a similar $100 bill, has become the first plastic note available through bank machines.

It is part of a broader upgrade of Canadian paper currency. In presenting the new bill in Quebec City, Bank of Canada governor Mark Carney called it state-of-the-art technology that will give Canadians confidence in the integrity of their currency.

Carney drew parallels between the currency and the subject matter it depicts.

"Just as the work of scientists on the Amundsen is expanding the frontiers of Arctic research, this new polymer series is expanding the frontiers of bank note technology," he said.

Carney said counterfeiting rates have plummeted in recent years, adding the new currency series would allow Canada to remain ahead of counterfeiters.

(Written by Alexander Panetta in Montreal)