HQ J. T. WILSON AND J. P. HILL. 
lamina for mz, but posteriorly it becomes free from its con- 
nection with the tooth. 
Stage VIII.—P. nasuta: pouch specimen. 
Length from tip of snout to root of tail: ; . 82 mm. 
Head length . - 5 : « OO es 
Upper Jaw.—tThe incisors are all strongly calcified. Their 
relations to one another are much the same as in Stages v and 
v1, only 74 is practically in the same horizontal plane as 23 and 
placed labially. The fifth incisor, however, as in the stages 
mentioned, appears distinctly on a higher plane as well as 
lingually from i+. There is a hiatus between 72 and £ in 
which no tooth appears in the coronal sections. Here the 
dental lamina is present in a disintegrating condition. Its 
deepened character becomes apparent as it approaches the 
canine, and its distal portion is somewhat swollen but quite 
irregular in outline, due to invasion by connective tissue 
assisting in its disintegration. Occasionally traces of its ori- 
ginal connection with the Malpighian layer may yet be seen. 
The second premolar and the first molar have become so 
approximated that they partly overlap. The deciduous pre- 
molar occupies a position labially and superficially to the 
hinder part of the former and directly superficial to the an- 
terior end of the latter, all three teeth appearing together in 
a number of the coronal sections. The Anlage of p3 is strongly 
developed by the lingual side of dp#, especially opposite its 
posterior part. The residual dental lamina, of which it forms 
the deepest part, has lost its superficial connection with the 
oral epithelium, though traces of such a connection here and 
there appear. The greater part of the superficial moiety of 
the lamina shows the extreme irregularity of outline due to 
progressive disintegration, and a number of rounded cell- 
nests or ‘epithelial pearls” are developed in connection with 
it. The deeper (distal) portion, forming the Anlage of p4, is 
very thick, and is found to develop quite abruptly a labial 
lobe. A few sections behind, this is seen to form the labial 
