490 J. T. WILSON AND J. P. HILL. 
nation of much later stages shows that they disappear as such, 
and that the enamel-organ of p3, when finally elaborated, is 
a simple and single rounded cup-like structure. 
A comparison of sagittal series with the horizontal and 
coronal of this stage proves that the ingrowths of connective 
tissue shown in the horizontal section are neither mere pits 
nor simple cross-furrows, but that they are circular furrows 
surrounding, and partially isolating, two rounded projections 
of the labial face of the lamina marked a and 6 in fig. 49. 
How these two knobs—for such they are definitely proved to 
be—are related to the process of formation of p2, we are not 
in a position to say. That they are no mere accidental out- 
growths is shown by the fact that they are present, under only 
slight modification in form, in the next stage (v, fig. 50). 
Nevertheless, in still later stages the regularity of the arrange- 
ment is lost, and the lamina simply appears irregularly thick- 
ened, until finally out of this thickening a quite simple and 
normal cup-like enamel-organ arises. 
A superficial criticism, having regard only to our fig. 49 of 
the present stage and fig. 50 of the next, Stage v, might be 
disposed to claim the indentations there represented as exam- 
ples of supposed primitive papillze whose fusion would consti- 
tute p32. It is just remotely possible that here we do have 
‘phenomena that ought to be interpreted by some fusion 
hypothesis, though we are strongly inclined to think otherwise. 
In any case if we do here meet with a case of fusion the 
structures that are fused are not dermal papille, for the 
structures which in some sections are suggestive of papille are 
merely cross-sections of the fibrous connective tissue occupy- 
ing certain circular grooves which circumscribe knob-like pro- 
minences of the dental lamina near its fundus. 
We may further point out that so far, and after careful study, 
especially of these earlier and plastic stages, we can (with 
Leche) find no support for Woodward’s statement that p3 
(i.e. the successional tooth) takes its origin from the dental 
lamina morphologically in front of dp2 (i.e. the milk molar), 
and is therefore probably in series with it. 
