574 J. T. WILSON AND J. P. HILL. 
of the development of a molar enamel-organ, of several meso- 
dermal papillary upgrowths prior to any marked differentiation 
of the enamel epithelial germ. These upgrowths he confi- 
dently interprets as the homologues of the originally distinct 
denticles of which, in his view, a complex tooth is really built 
up (cf. 29, fig. 1). 
Woodward has remarked upon Rése’s attempt to prove 
his theory in the case of the chameleon, “ where the back teeth 
are each composed of three cones, which, according to him 
(Rése), arise independently of one another,” to the following 
effect :—this is true to a certain extent, but these cusps develop 
under a common enamel-organ, and there is no indication of 
their ever having possessed independent organs, as would have 
been the case if they were distinct teeth, there being merely a 
differentiation of the cylindrical enamel-epithelium over each 
cusp, which Rése considers sufficient evidence in favour of his 
view’? (14, p. 446). 
We have occasionally come across appearances which at 
first seemed to suggest multiple papillary upgrowths in con- 
nection with the developing molar lamina. Thus in fig. 69, 
though the whole of the surrounding connective tissue has not 
been represented, it is plain that the irregularities of the labial 
surface of the dental lamina might (if the connective tissue 
were all filled in) suggest multiple papillation. But, as we 
have already shown in our previous references to this figure, 
this view would be quite erroneous. The true and only papilla 
of m2 is marked “mp.” Fig. 69 may be compared with figs. 
68a and 70. So far as our observation and experience go a 
truly multiple papillary character is never found in the 
earliest stages of development of a marsupial molar. At its 
first differentiation as such the molar enamel-organ is as 
simple, single, and uncomplicated in form as any incisor 
enamel-organ. And as certainly we find that we can watch 
the ontogenetic evolution of the marsupial molar cusps by a 
gradual differentiation of the primitively simple cup-shaped or 
bell-shaped enamel-organ. 
It would appear, however, that such a statement as the 
