460 J. T. WILSON AND J. P. HILL. 
The posterior limit of this rudiment of 7; may be recognised 
by a marked diminution in the sectional area of the lamina, 
~ which continues back quite small until it again expands into 
the typically elongated canine Anlage. The lamina in this 
region is relatively much elongated on transverse section. It 
does not, however, penetrate the deeper tissues in a vertical 
direction, but is diverted rather mesially, parallel with, and 
pretty closely adjacent to, the deep surface of the oral 
epithelium. In it a very interesting step in differentiation 
may be observed in the shape of avery slight but unmistakable 
attempt at the formation of the enamel-organ of the milk 
canine (fig. 18, d.;). This is just on the point of becoming 
cup-shaped, and the dermal papilla (mp.d;) is beginning to 
form. In the succeeding stages this Anlage -will be followed 
through the course of its evolution. Here, as in the other 
examples of milk Anlagen, the structure is first developed not 
only on the labial aspect of the common canine enlargement 
of the dental lamina, but opposite its anterior part, the 
swelling attaining its maximum development just behind the 
milk rudiment. 
As is the case in the upper jaw, the premolar portion of the 
lamina behind the canine Anlage is small and presents no 
local differentiation until we reach the region of the last 
premolar (dp;). Here the dental lamina becomes much 
enlarged in all its dimensions, and the bulbous mass becomes 
indented labially by the large dermal papilla of d.p.z (the 
“milk molar”). Its characters are so closely similar to 
those of the corresponding organ in the upper jaw that the 
figures of the latter may suffice for both (figs. 8 and 9). 
Fig. 14, however, illustrates the appearance seen in sagittal 
section. 
The molar region of the dental lamina is in a precisely 
similar condition to that exhibited in the upper jaw. There is 
only a slight indication of the differentiation of the first molar 
enamel-organ. For the most part the molar lamina forms 
simply a slab-like lamina of considerable dimensions, extend- 
ing backwards, and continuous in front with the milk premolar. 
