(n)akt

Recently I was at the "Kandinsky" exhibition in Munich. I noticed a few paintings were titled "Akt mit Katze" or "Akt mit blauem Hintergrund" which were translated as "Nude with cat" or "Nude on blue background". I thought at first it was a spelling mistake, because 'nude' in german surely is 'nakt' not 'akt'. Does anyone have a clue why the N is missing? The paintings are from the early 20th century.

Thanks.