Both claws, and their adjacent legs, have matching half-circle notches in them that line up to create a circle-shaped opening when the limbs are tightly pulled against one another. This tubular round opening is called a foramen.
Both claws, along with their adjacent legs, have matching half-circular indentations that merge to form a circular opening when the limbs are tightly pulled together. This cylindrical opening is referred to as an aperture.