I can't help but think when I look at this photo that Anna and Marcel are very alike. I think it is something to do with their similar expressions around the eyes and mouth. The fact that they have the darkest eyes and skin of all the kids too make them look closer than say Marcel and Léon, or Anna and Lots.
It's funny, for many years I was told Marcel had nothing of me and was only like his father. Since Anna was born I also constantly hear how she is her father's double. But I guess if they are alike they must both have some hidden Mummy traits given they have different fathers!