Figure 1: the ideal head and skull. Eyes should be dark (except in chocolates) and oval. Round eyes are a fault.
Figure 2: excessively pronounced stop, low set and folded ears.
Figure 3: short, snipy jaw, with high-set ears.
Figure 4: ideal head, seen from above, with the jaw tapering uniformly to the nose.
Figure 5: faulty jaw, pinched in between the eyes and nose.
Figure 6: shows dewlap (baggy skin under the neck). The skin should fit closely all over the body.