does not happen to the i principale’ in the same dentition as classified
by M. de Blainville.
Passing next to the comparison of the dentition of Quadrupeds
more closely allied, and of the same natural order, we find the upper
‘ principale’ in the Lion thus described by M. de Blainville :
Celle-ci, bien plus grande et de forme triangulaire et subtriquètre
à sa couronne, avec le sommet submédian et peu pointu, est pourvue
en avant et un peu en dedans d’un tubercule basilaire peu marqué,
et de deux en arrière, dont l’un, le postérieur, est une sorte de
talon. Osteogr. de Felis, p. 55. Then follows the description of
the first I arrière-molaire’, which is rightly termed 1 carnassière
supérieure . If we turn to M. de Blainville’s account of the dentition
of Viverra we find that “ La principale d’en haut est aussi un peu
moins carnassière par plus d épaisseur du talon interne antérieure
et par moins de largeur du lobe postérieur.” ‘ Oste'ogr. de Viverra,
p. 42.’ The Author is comparing it with the premolar in front of
it, which is, in fact, the analogue of his 1 dent principale’ in the
Lion, the ‘ dent principale’ in the Viverra being the analogue of
the dent carnassière in the Lion. Thus the characters adopted
by M.\ de Blainville, not only fail in the determination of the
analogous teeth in different orders but also in different genera of
the same order, and, according to his first determination of the
Feline formula, even in the upper and lower jaws of the same
species.
Neither is the author of the ‘ Ostéographie’ more consistent
with himself in a later portion of his great Work : in the Fasciculus
on the | Ostéographie de Hyæna,’ (p. 25) he adopts a third
formula for the molar series of the genus Felis, apparently from
Daubenton, which differs both from that which is given 'in the
‘ Generalities on the Carnivora,’ (p. 69), and from that described
in detail in the jj Ostéographie de Felis’ (p. 55) : it is as
follows :— t + 4 + I ; i.e. two premolars, one principal, one true
molar above ; and one premolar, one principal and one true
molar below ; not any remark being made on its discrepancy with
the other formulae. But neither is this third view more true to
nature, than the two views previously proposed by M. de Blainville
in, the same Work ; for, according to the natural characters of the
molar series, the typical Felines have not two, but three premolars
on each side of the upper jaw, and two premolars, instead of one,
on each side of the lower jaw. I have come to the conclusion,
•therefore, after a long and patient series of researches upon both
the deciduous and permanent dentition of the Mammalia, that a
‘ molaire principale’ does not exist in nature, that its characters
as defined by M. de Blainville are artificial, and that they utterly
fail, or mislead, in their application to a philosophic determination
of the analogous teeth in the different genera of placental and
terrestrial Mammalia.
Having premised thus much in explanation of the grounds
which have prevented my adopting the dental formulae assigned to
the genera of Mammalia, not only by M. de Blainville, but by the
Cuviers, I have only to add an explanation of the principles of
the -formulae substituted for them in the present work. As respects
the molar teeth, I believe my classification to be founded on a more
important, a more constant, and therefore a more natural character
than those of ‘ form,’ ‘ size,’ or ‘ relative position.’ According to
the law of development the series of true molars begins with that
tooth which rises into place behind the last of the deciduous series
and includes all behind it ; all the permanent molars in front of this
series are premolars. I have already exemplified the application of
this law to the determination of the analogous true-molar teeth in
the Lion and Man, and I may observe that it is equally applicable
to the identification of every tooth in the molar series. According
to it, the first upper true molar tooth in the Human Subject,
(‘ principale’ of M. de Blainville), is the analogue of the last, or
tubercular molar in the upper jaw of the Lion; the first lower
true molar tooth in Man answers to the lower sectorial tooth
in the Lion; the upper sectorial in the Lion is essentially the
same tooth as the second superior bicuspid in Man; the second
upper premolar of the Lion answers to the first upper bicuspis in
Man; the first small premolar in the Lion has no analogue in the
Human dentition; the two premolars in the lower jaw of the
Lion correspond with the two inferior bicuspids in Man.
The natural character of the premolars as a distinct subdivision of
the molar series is shown by a certain independence in their time of