4.70 J. T. WILSON AND J. P. HILL. 
formed by the elbow-lke projection marked “c.dl.”? in the 
figure, and the flattened surface between c.d/. and the apical 
point of the whole enlargement would represent the site of the 
future enamel cup. However this may be, the one specially 
striking and important feature of this general canine Anlage 
is the presence, near its “ neck,” of a very perfect miniature 
enamel-organ in the cup-shaped stage. ‘This structure 
projects directly outwards in a labial direction from the 
proximal portion of the dental lamina, and in it we 
recognise, in accordance with the views we have set forth 
in the Introduction, the true rudimentary “milk” canine 
(fig. 20, d®). 
In fig. 22 we have shown another horizontal section through 
the upper jaw of this stage, through the same region as, but at 
a higher level than, the section illustrated in fig. 21. In this 
section we remark the canine thickening of the dental lamina 
¢, and its more attenuated prolongation backwards into the 
premolar region (p+di.). Beside the thickened canine portion, 
the enamel organ of d£is seen. Further important reference 
will be made to this figure later on. In the meantime we 
would draw attention to the fact that the minute, and up 
to this stage perfect, enamel-organ described above 
is entirely homologous in position and relations 
with those small lobular outgrowths of the epi- 
thelium of the dental lamina situated labially from 
the Anlage of the four hindmost incisors, which we 
have interpreted as representatives of enamel- 
organs of deciduous incisors. And it is not mate- 
rially diverse from these in regard to its chrono- 
logical position. 
Now if the serial homology with the incisor vestiges be 
granted—and we think it is impossible to avoid such a con- 
cession—this at once establishes the title of these vestiges to 
be regarded as true representatives of the enamel-organs of a 
tooth-generation preceding the permanent teeth. And in our 
opinion this generation is homologous to the milk series of 
Eutheria. 
