ELEPHAS ANTIQUUS—RIDGE FORMULAE. 
49 
and 
t in 
fully 
I the 
i for 
Men- 
molar 
in the 
irately 
dionalis equals the lowest expression of the last molar in E. antiquus, so that as far as the 
numbers of ridges are concerned we find Elephasprimigenius, Elephas antiquus, Elephas 
meridionalis, and Elephas Namadicus, meeting at their extremes, and showing thereby 
that to sharply define their ridge formulae, by striking an average in each case, is no 
exponent of the actual range of variation to which every member of the dental series is 
more or less subject. 
The above suffices to show how much the molars of Proboscidia vary in the number of 
their ridges, and how arbitrary it would be to formulate an average in the case of any one 
species or even any one member of a dental series. The stress laid by Dr. Falconer on 
the dental formulae as diagnostic of species of Mastodon and Elephant is evident 
when the fossil materials come to be differentiated. But it is also clear that in 
correlating members of the genus Elephas any formula professing to furnish an average 
number of plates per molar must of necessity be subject to exceptionable conditions. 
The data by which fossil species are determined are too few at present to admit of 
casting a mean, whilst the desirability of tracing evolutionary characters between them is 
more or less thwarted by setting up a definite formulary in each case, more especially 
where two or more forms of Elephants assimilate closely. The very fact that the dental 
elements of any one species are subject to variation as regards numbers, and that one or 
more particular member of the series presents exeeptional conditions, is of the utmost 
importance in estimating the character and affinities of the species in question when taken 
in connection with the sculpturing of the crowns of worn disks. 
I have correlated in the foregoing comparisons the dentitions, as far as I have been 
enabled to make out, of the seven best known species of Elephants including the recent 
and fossil. It is apparent, however, that there are aberrant forms, such as the Elephas 
Columbi (Falconer) and the Elephas Armeniacus (Falconer), 1 with which comparisons 
should be made; but I have not ventured on this undertaking, inasmuch as, in 
order to do justice to even the Elephant here described, it is necessary to compare also 
the entire Elephantine remains from the Sewalik Ranges of the Himalayan Mountains, the 
affinities of which with European or North American species are worthy of far more 
attention than has been bestowed on that subject. 
Summary. —It will be apparent from the data furnished in the previous pages that the 
molars of E. antiquus differ considerably individually as regards dimensions and number 
of ridges in both the upper and lower jaws ; thus in the upper jaw the differences between 
the extremes in the various members of the series may be instanced as follows: 
The difference between the maximum and minimum length in the upper jaw of 1 2 
(milk molar) is Off, of II 3 1'2, of III 4 TO, of IV 5 2‘5, of V 6 2 5, of VI 7 3'3 inches. 
In the mandible the differences of length are : for l 8 ?, for II 9 0'5, for III 10 1*3, for 
IV 11 2-3, for V 13 2-8, for VI 13 3ff. 
1 ‘Pal. Mem.,’ vol. ii, pp. 212 and 247. 2 See page 11 ,ante. 3 p. 16. 4 p. 20. 5 p. 26. 
6 p. 31. » p. 46. 8 p. 11. 9 p. 16. 10 p. 20. 11 p. 26. 12 p. 31. w p. 46. 
7 
