DEVELOPMENT AND SUCCESSION OF THETH IN PERAMELES. 495 
organ of the latter; and it is from it, and not from the lamina 
morphologically in front of dp, that p? is subsequently de- 
veloped. We have put our re-interpretation of Mr. Wood- 
ward’s facts in frankly dogmatic form for the sake of clearness. 
There is too much unavoidable uncertainty about any question 
of this kind to encourage a genuinely dogmatic attitude in 
regard to it. And we may, indeed, with Leche, admit after 
all the possibility of dp® arising in front of p32 without 
concluding, with Woodward, that the teeth so arising belong 
to the same series. At the same time the facts in Perameles 
do not permit us to entertain any doubt with regard to the 
origin of dp*, however it may be in the case of Petrogale. 
Nor do our investigations in Marsupials lead us to side with 
Leche in his view that the germs of the permanent teeth do 
arise in front of those of the milk-teeth. Judging from the 
observations already detailed with regard to the position of 
the early rudiments of the vestigial milk incisors, we must be- 
lieve that the Anlagen of the permanent teeth arise side by 
side with those of the milk-teeth, though the latter are placed 
rather opposite the anterior portions of the former. This we 
have already seen to be originally the case in the region of the 
first lower incisor of Perameles. Nevertheless at a com- 
paratively early period the vestigial milk enamel-organ comes 
to lie opposite the hinder end of the permanent tooth, so that 
here the primitive relation comes to appear reversed. 
Woodward calls attention to the anomalous eruption of p3 
in Perameles rather in front of its “ supposed” pre- 
decessor dp. 
But, after all, the point of eruption of a tooth is of 
secondary importance, and we find, on the other hand, that 
not only at its first appearance, but during the very long 
latent period which precedes its elaboration as a cupped 
enamel-organ, the germ of p3 is placed, not in front of, but 
opposite to dp3, 
it would be difficult to draw any other conclusion from our 
fig. 48, and here we are in a position to state that there is 
absolutely not the slightest scrap of evidence tending to prove 
