DEVELOPMENT OF THE FACE. 413 



lip. At the same time, there is a projection from above, ex- 

 tending between the- two superior projections, which is called 

 the frontal, or intermaxillary process. This extends from 

 the forehead, that portion which covers the front of the cere- 

 brum, downward. The superior maxillary projections then 

 advance forward, gradually passing to meet the frontal pro- 

 cess, but leaving two small openings on either side of the 

 median line, which are the openings of the nostrils. The 

 upper portion of the frontal process thus forms the nose ; but 

 below, is the lower end of this process, which is at first split 

 in the median line, projects below the nose, and forms the 

 incisor process, at the lower border of which are finally devel- 

 oped the incisor teeth. As the superior maxillary processes 

 advance forward, the eyes are moved, as it were, from the 

 sides of the head and present anteriorly, until finally their 

 axes become parallel. These processes advance from the two 

 sides, come to the sides of the incisor process beneath the 

 nose, unite with the incisor process on either side, and their 

 lower margin, with the lower margin of the incisor process, 

 forms the upper lip ; but, before this, the two lateral halves 

 of the incisor process have united in the median line. At 

 the bottom of the cavity of the mouth, a small papilla makes 

 its appearance, which gradually elongates and forms the 

 tongue. 



While this process of development of the anterior por- 

 tion of the first visceral arch is going on, at its posterior por- 

 tion, we have developing, the malleus and incus, the former 

 being at first connected with the cartilage of Meckel, which 

 extends along the inner surface of the inferior maxilla, the 

 two cartilages meeting at the chin. The cleft between the 

 first and the second visceral arch has closed, except at its pos- 

 terior portion, where an opening is left for the external audi- 

 tory meatus, the cavity of the tympanum, and the Eustachian 

 tube. 



At the same time, the second visceral arch advances, and 

 forms the stapes, the styloid ligament, and the lesser cornua 



