4.80 J. T. WILSON AND J. P. HILL. 
distinctly swollen, is exceedingly well developed (fig. 55) 
along the whole extent of the tooth (¢;) so that the latter 
has come to appear as a huge appendage of the liberated 
lamina. 
In the present stage no such differentiation has occurred, 
and the whole of the large dental lamina remaining over after 
the differentiation of diz appears for the present totally con- 
verted into an enamel-organ for 77. Thus the sequence of 
phenomena observable in this series of three stages (11, III, 
and iv) in the case of this particular region goes far to illus- 
trate and support our contentions as to the nature and con- 
ditions of occurrence of a residual dental lamina, the so-called 
“ Krsatzleiste ” of Rose. 
As the papillated Anlage of 7; is traced backwards it 
gradually diminishes in sectional area, becoming at the same 
time more consolidated by loss or marked reduction of the 
looser epithelial cells in its interior, which become the steilate 
tissue. When the last trace of papillation has disappeared 
posteriorly, the structure is seen to be again a mere undif- 
ferentiated dental lamina transitional from the first to the 
second incisor region. In the latter situation it swells out 
again, and at the same time becomes slightly indented below. 
There is also a somewhat denser aggregation of connective- 
tissue cells in relation to this indentation than elsewhere in 
the fibrous capsule, and the cellular accumulation forms a 
faint elevation, corresponding to the indentation of the enamel- 
germ. 
This condition of affairs corresponds to what we have 
already noted in connection with the upper incisors. Beyond 
the Anlage of 73 the dental lamina runs for a short distance 
almost transversely outwards, and then swells into the Anlage 
ofiz. This relationship is very striking. At first we were 
puzzled by the appearance of the coronal sections in this region, 
for both 7; and zz appear in the same section (fig. 34), and 
the relation of the intervening part of the dental lamina seems 
obscure. <A casual examination would suggest the idea that 
the Anlage of i; is morphologically in the same transverse 
