DEVELOPMENT AND SUCCESSION OF TEETH IN PERAMELES. 457 
amongst those which subsequently attain maturity, which as 
yet exhibits the least trace of papillation. The precocious 
character of its development is well illustrated in fig. 10 
(dp*), showing in sagittal section its relation to the oral 
epithelium (0.e.) and to the molar portion of the dental lamina 
(dl.) behind it, which is cut vertically in the sagittal plane of 
the section. 
The molar portion of the dental lamina is massive and well 
developed for quite a considerable distance behind dp3, as 
may be seen in fig. 10. At first it is merely flask-shaped on 
transverse section, but soon its cross-section alters in shape 
by its distal margin bulging out obliquely in a labial direction. 
This constitutes the Anlage of m+, and is seen in fig. 1] to 
exhibit a very slight depression at its fundus. . . . Opposite 
this depression the connective-tissue cells are aggregated to 
form the very earliest Anlage of a dermal papilla (mp.m+). 
Both in front and behind, the swollen Anlage gradually 
diminishes in thickness. It is worthy of special remark that 
here we have the very youngest stage in the differentiation of 
a separate molar enamel-organ, and that in this there is not 
the slightest indication of a composite character of the dermal 
papilla whose earliest stage of evolution is here exemplified. 
It is, from the first, single and individual. In the next 
succeeding stage we shall find that this incipient enamel-organ 
has rapidly attained a typical cup-shaped or even “ bell- 
shaped” (‘‘glockenformig”’) character, and has “caught up 
with” dp2 in its progress towards full differentiation. 
Behind the Anlage of m+ the molar lamina gradually 
diminishes in size, and finally comes to a rather abrupt termi- 
nation in a somewhat truncated hinder extremity. 
It will be evident from fig. 10 that at least the major portion 
of the dental lamina in the molar region is directly continuous 
with the deep surface of the oral epithelium. If the third suc- 
ceeding section of this series were also figured, it would be seen 
that this continuity of the lamina with the oral epithelium 
extends right up to the very hindmost end of the molar lamina. 
It is thus evident that the dental lamina in the molar region 
