Pink-eye and albino are two recessive traits found in the deer mouse Peromyscus maniculatus. In pink-eyed mice, the eye is devoid of color and appears pink because of the blood vessels within it. Albino mice are completely lacking color, both in their fur and in their eyes. F. H. Clark crossed pink-eyed mice with albino mice; the resulting F1 had normal coloration in their fur and eyes. He then crossed these F1 mice with mice that were pink eyed and albino and obtained the following progeny. It is hard to distinguish between mice that are albino and mice that are both pink eyed and albino, so he combined these two phenotypes