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OK THE FORMATION OF THE TEETH IN THE FCETUS. 1 1 !>

begin on the edge of the first Tncisores. The Cuspidati are
not in the same circular line with the rest, but somewhat on the
outside, making a projection there at this age, there not being
sufficient room for them. (w)
In the sixth, or seventh month, the edges, or tips, of all
these five substances have begun to ossify, and the first of them
is a little advanced ; and besides these, the pulp of the sixth
Tooth has begun to be formed ; it is situated in the tubercle of
the Upper-Jaw, and under and on the inside of the Coronoid
Process in the Lower-Jaw : so that at this age, in both Jaws,
there are in all twenty Teeth begun to ossify, and the stamina
of twenty-four, (x) They may be divided into the Iucisores,
Caspidati, and Molares ; for at this age there are no Bicuspides,
the two last teeth in each side of both Jaws having all the
characteristics, and answering all the purposes of the true
Molares in the adult, though Avhen these first Molares fall out,
their places are taken by the Bicuspides.
The Teeth gradually advance in their ossification, and about
the seventh, eighth, or ninth month after birth, the Incisorcs
begin to cut or pass through the Gums first, generally, in the
;
Lower-Jaw. Before this time the ossifications in the third
Grinder, or that which makes the first in the adult, are begun.

a whole under the microscope, appear like a clear band. It is on the
surface of the bulb beneath the deep face of the enamel organ that the
first cells of the dentine appear. Such is a sketch of the germs of the
dental follicles, as seen by these observers. We shall hereafter notice
the subsequent changes which are said by these observers to take place
in the process of development. (1)]
(w) [An instance of an accordance in the embryonic state with the
more general type.]
(x) [More recent observations refer the commencement of dentine to a
somewhat earlier period. By the end of the fourth month, thin caps
of dentine may be found surmounting the pulps of all the milk teeth,
and a little later on the first permanent molars. According to Robin
and Magitot, the first appearance of the tooth, properly so called, takes
place between the eightieth and eighty-fifth day in the lower middle
incisor.]
(1) Robin and Magitot, op. cit.