Maurice made an observation on a vice of conformation of the lower jaw which rendered lactation impossible, probably causing the death of the infant on this account.

Tomes gives a description of a lower jaw the development of the left ramus of which had been arrested.

Canton mentions arrest of development of the left perpendicular ramus of the lower jaw combined with malformation of the external ear.
Exaggerated prominence of the maxillaries is called prognathism; that of the superior maxilla is seen in the North American Indians.

Inferior prognathism is observed in man as well as in animals.

The bull-dog, for example, displays this, but in this instance the deformity is really superior brachygnathism, the superior maxilla being arrested in development.
Congenital absence of the nose is a very rare anomaly.