EAELY GROWTH OF THE BONES OF THE HUMAN FACE. 
167 
maxilla is in front of the canine socket when the latter is present, when absent the 
relation of the suture to the maxilla virtually remains unaltered. (2) The prsemaxilla, 
as it is more correctly named for these animals, is prolonged superiorly to a point which 
ascends to a varying distance, or is cut short abruptly. In any case, whatever be the length 
of the posterior margin, a groove is found in the anterior edge of the superior maxilla ; 
and into this the wedge-shaped margin, broad or narrow (sometimes almost incisive, 
as in the sheep), of the prsemaxilla is inserted, and is thus embraced, as it were, by the 
front border of the upper jaw. (3) The praemaxillse carry the incisor teeth, when pre- 
sent. (4) They articulate in the middle line, sometimes leaving a notch in front for a 
continuation forward of the septum. (5) They form more or less of the front of the 
palate, of the boundaries of the incisive foramina, and of the complete or partial septum 
which separates them (see Plate XIII. figs. 9 & 10, Plate XIV. figs. 1, 2, 3, 4). 
On the superior maxilla during foetal life there may be seen in many animals, in front 
of the canine socket, a slight projection which appears to be analogous to the incisor 
process of the corresponding human bone. This may be observed in a foetal Pig (Plate 
XIII. fig. 3). In the mammary foetus of a Kangaroo also there is a short thick process 
which projects considerably forwards and downwards in remarkable contrast with the 
corresponding but elongated portion of the adult bone (Plate XIII. fig. 5). 
Passing to an examination of the human foetus, it is evident, from the shape and direc- 
tion of the incisor process (which is best examined in a foetus 4 - 3, being then easily de- 
tached from the intermaxilla), that it passes across the anterior boundary of the nostril 
as the latter is continued forwaxd to the middle of the lip (Plate XIV. figs. 5 & 7). This 
boundary above is partly covered by the nasal process, below the palatal portion of the 
superior maxilla ends abruptly behind it, and between the two it is that the incisor 
process crosses, and indents the orifice of the nostril. 
The membrane inflected by the incisor process extends from the middle line (where it 
is continued forward to be connected with the process of the maxillary lobe which joins 
it on either side to complete the upper lip), partly below and then behind the incisor 
process, fills the fissure between that and the palatal, and is continued up behind the 
nasal process ; the groove on the inner surface of this process corresponds with the edge 
formed by the bending in of the anterior membranous boundary of the nostril, and in 
the membrane continued back from the angle thus formed there is developed the plate 
of bone which constitutes the anterior inner or nasal wall of the antrum and the 
channel for the nasal duct, whilst in the membrane which lies anterior to the groove the 
intermaxilla of either side originates. 
In a foetus 2'3 the intermaxilla consists of deposits of bone about the posterior edge of 
the incisor process, which subsequently grow down to form the plate of bone on the 
inner side of the middle incisor socket, and the posterior wall of the incisor sockets be- 
low and internal to the course of the incisor branches of the dental nerve. The front 
