The development of the face depends, as I have already shown, upon the enlargement and fusion of the mouth and nose cavities, and upon the later partial separation of the nose and mouth and the nose cavities, leaving the posterior nose open. It depends further upon the growth and specialisation of the face region, of which the elongation is the most prominent indication, and finally upon the development of a prominent external nose. The relations of face to cranium in embryology have already been described. When the medullary tube of the notochord enlarges to form the brain the end of the head bends over to make room for that enlargement. The bending of the head carries the mouth plate, which is to be the mouth, over to the front of the head. The changes which develop the mouth cavity are the growth of the brain and the increase in size of the heart cavity, which expand to the front, leaving the mouth cavity between them. The mouth cavity represents two gill-slits united in the front line. The nose is formed from two olfactory plates situated just in front of the mouth and in contact with the fore-brain. These olfactory plates grow in size by the increase of tissue, and the resulting pits pass away from the brain. At first these pits, although widely separated by what is called the nasal process, communicate freely with the mouth. The nasal process includes the origin of the future nose and of the future intermaxillary region of the upper lip. The human face is modified backward from the vertebrate type. It is an additional illustration of the degeneracy of a series of related structures for the benefit of the organism as a whole. The progress of development of the face in the vertebrates is checked in man. First, as Minot remarks,[196] because the upright position renders it unnecessary to bend the head as in quadrupeds. Second, because the enormous cerebral development has rendered an enlargement of the brain cavity necessary. This has taken place by extending the cavity over the nose region as well as by enlarging the whole skull. Third, because the development of the face is arrested at an embryonic stage; the production of a long snout being really an advance of development which does not take place in man. From what has been said of the relations of the dermal bones to the nose and face in the chapter on the skull, it will be obvious that these must follow the same laws as to degeneracy as the skull itself. These checks from degeneracy in arrest of development are apt to affect most obviously the unilateral development of the face. From this results the exaggerated asymmetry so frequently observed. Jacob Baumler, the founder of the Zoar community of the United States, a religious fanatic, had a very marked asymmetry of the face and the mind of a degenerate. His orbits were unequal, one being exceedingly large and the other correspondingly small.