Tucked under her dress? Poking through a hole behind her? Was Leslie actually missing a leg? Never mind that women did not wear 1960s high heels in 1888, but that was a standard convention at the time along with modern make-up and hairstyles. No, there's something very peculiar here. All I can think is that the illustrator (or someone at Disney) didn't like the leg he painted on the illustration board, pasted a new one on top and it fell off on the way to the printers. And then no one noticed? I'd be interested in hearing other theories.