EAELT GROWTH OF THE BONES OF THE HUMAN FACE. 
165 
There is no evidence in the human foetus that the palatal-alveolar is ever a distinct 
process, although its ossification occurs a little less early than that of the other por- 
tions. In a foetus T5 bone-granules are seen ranged along the edges of the alveolar 
plate, which they surrounded like a ring, and extend into the back part of the palatal 
process ; but whilst the nasal and orbital portions of the bone are comparatively well 
shaped, the palate is but a ridge standing in towards the middle line, and is separated 
by a wide angular notch, the base of which is towards the middle line, from the incisor 
process. 
In a foetus 2’3 the bone presents the following appearances. Taking a point below 
the infraorbital notch as a centre, three processes are traced from it : — (1) The nasal forms 
a thin plate having the permanent shape of the process, but the ridge for the turbinate 
bone, the vertical thickening of its lower nasal surface, and the nasal groove are wanting. 
From its base a smooth plate of bone passes forward, the centrebit, as it were, of the 
incisor portion, chief part of the roof of which it ultimately forms, and to this hitherto, 
I believe, unrecognized portion the name of incisor process may be rightly given (Plate 
XIV. figs. 5 & 7). A channel or groove ascends from, and is continuous with, the fissure 
between the incisor process and the front edge of the palatal, and ends about halfway 
up the inner surface of the nasal process. (2) The palatal-alveolar extends with a 
slight slope inwards and backwards. Its nasal surface has no distinguishing mark, but 
on that of the palate a slight ridge indicates the situation of the base of the inner alve- 
olar wall. (3) The orbital, divided on the upper surface from the palatal-alveolar pro- 
cess by a deep groove (narrow in front, where it forms the infraorbital fissure, and com- 
paratively wide posteriorly), and continued backwards above the alveolar plate to end in 
an articular surface for the malar bone. 
Below and anterior to the infraorbital fissure the maxilla is deeply notched to form 
the roof of the canine socket ; but there is no such notch, the lower border being uni- 
formly level in the maxilla of a foetus 1-5. 
A foetus 4*7, a second 6*7, and a third 9 inches long may be selected as illustrating 
the changes which occur during the early growth of the bone (Plate XIV. figs. 5 to 11). 
The outer surface of the nasal process becomes thickened and strengthened by bone 
deposits, which spread out above and laterally, forming in a foetus 4*3 the anterior wall 
of the sockets for the incisors, covering the canine notch, and reaching posteriorly be- 
yond the margins of the infraorbital fissure. In a foetus 6*7 they constitute a ridge 
below the facial portion of the orbital plate for the outer wall of the alveoli of the mo- 
lars, which gradually deepens hut only reaches the posterior part of the alveolar plate 
in a foetus 9 inches long. In the same order the inner wall of all the sockets is formed, 
but the inner and outer walls have not quite united posteriorly in a foetus 9 inches long. 
These plates of bone, excepting the inner and median walls of the incisor sockets, are 
produced in membrane continuous with that in which the gums are formed. 
The canine socket is isolated by lateral partitions of hone in a foetus 4 '3, the incisors 
begin to be separated in a foetus 6*7, but the division between the lateral and middle 
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