514, J. T. WILSON AND J. P. HILL. 
extends backwards for a considerable distance below both the 
succeeding teeth, and the third now extends considerably be- 
hind the second incisor. 
The deciduous premolar is now calcified right down to its 
root. The Anlage of pz exhibits a distinct but small and 
simple dermal papilla, while the proximal (“neck”) part of 
the lamina is irregular and contorted from the operation of 
degenerative processes. The three anterior molars are well- 
formed calcified teeth, and the dental lamina towards the 
posterior end of mz becomes well developed as a residual 
lamina for that tooth, and then exhibits the differentiating 
Anlage of mz. 
Stage [IX.—P. nasuta: pouch specimen. 
Length from tip of snout to root of tail 5 . 91mm. 
Head length. : 5 : . 40 
Upper Jaw.—The incisors are now more elongated and 
relatively narrower than in the preceding stages. Hach 
appears, in coronal sections, above the hinder part of the tooth 
in front, overlapping the latter considerably. The relation of 
15 to i4 is similar to that of 74 to 73, &c. 
The tips of all the incisors le near the oral epithelium. 
The canine appears above the hinder part of 23, overlapping it ; 
p+ occupies a similar relation to *, and p? to p+. 
Up to the premolar region the dental lamina is represented 
only by fragmentary and degenerated remains in the shape of 
broken-up and isolated groups of epithelial cells, which are 
best marked beside 72 and‘. In the anterior premolar region 
these degenerated remains continue to appear, though very 
sparsely in the region of the anterior part of the second pre- 
molar. After dp? appears in the section the remains of the 
residual dental lamina become more definite, and soon are 
arranged in definite laminar form, but are deeply placed and 
quite unconnected with the oral epithelium ; the relations of 
dp to the hinder part of p2 and to the residual dental lamina 
with the Anlage of p® are illustrated in fig. 67. The most 
