The inclination backward of the nose allows a free passage of the
air into the nostrils whilst the dog is holding his quarry. It is
apparent that if the mouth did not project beyond the nose, the
nostrils would be flat against the part to which the dog was fixed,
and breathing would then be stopped.

The upper lip, called the "chop," or flews, should be thick, broad,
pendant and very deep, hanging completely over the lower jaw at the
sides, but only just joining the under lip in front, yet covering
the teeth completely. The amount of "cushion" which a dog may have
is dependent upon the thickness of the flews. The lips should not
be pendulous.

The upper jaw should be broad, massive, and square, the tusks being
wide apart, whilst the lower jaw, being turned upwards, should project
in front of the upper. The teeth should be large and strong, and the
six small teeth between the tusks should be in an even row. The upper
jaw cannot be too broad between the tusks. If the upper and lower
jaws are level, and the muzzle is not turned upwards the dog is said
to be "down-faced," whilst if the underjaw is not undershot he is
said to be "froggy." A "wry-faced" dog is one having the lower jaw
twisted, and this deformity so detracts from the general appearance
of the dog as seriously to handicap him in the show-ring.

The underjaw projects beyond the upper in order to allow the dog,
when running directly to the front, to grasp the bull, and, when
fixed, to give him a firmer hold. The eyes, seen from the front,
should be situated low down in the skull, as far from the ears, the
nose, and each other as possible, but quite in front of the forehead,
so long as their corners are in a straight line at right angles with