500 J. T. WILSON AND J. P. HILL. 
the third especially showing a distinct advance from the pre- 
ceding stage. It is now triangular and pointed in coronal 
section, and possesses a distinct dentine cap, as also do the first 
and second. 
The dental lamina is definitely interrupted between i+ and 
12, but otherwise it is continuous, though often greatly re- 
duced in size, throughout the rest of the incisor region, and it 
retains its connection with the oral epithelium. 
Towards the anterior part of the first incisor region irre- 
gular epithelial cell-processes spring from the oral epithelium 
close to the root of the dental lamina, similar to those men- 
tioned in connection with the corresponding region in Stage 
Iv (figs. 43—46). 
The residual dental lamina is still clearly marked by the 
sides of 74 and 72, but it is now considerably reduced in size, 
absolutely as well as relatively to the tooth-germs. The resi- 
dual dental lamina in the region of i has become definitely 
established, and indeed it now closely resembles that of 7+ 
and i2, In each case, though forming a distinct and freely 
projecting laminar downgrowth beyond the connecting stalk 
of the tooth-germ, it is already a somewhat attenuated and 
insignificant structure. We should certainly not be war- 
ranted in following Leche by reading any special importance 
into its persistent presence at this stage. It is plainly steadily 
disappearing. 
The fourth and fifth incisor enamel-organs are in a much 
less advanced stage than those in front. They are still rela- 
tively shallower and cup-like, with rounded papillz, much as 
they were in Stage tv. They still appear as modifications of 
the dental lamina which is directly continuous with the lin- 
gual lip of their cup-like body, and no residual lamina has as 
yet differentiated itself from them. As one might expect, 
the portion of the lamina with which they are continuous is 
bulkier, i.e. less reduced, than it is in regions where tooth- 
germs have attained a more advanced stage of development. 
The lamina behind 72 passes directly and with a somewhat 
abrupt deepening into the canine lamina. This, with the 
