SIWALIK AND NAEBADA PEOBOSCIDIA. 
17—198 
Dentition oe the Elephantidje. 
The dentition of the Elephantidce is perhaps more remarkable than that of any 
other group of the Mammalia, in regard both to the structure of the teeth and in 
their mode of succession, and is evidently the product of a long course of special- 
ization. With regard to the structm’c of the teeth, I shall not enter into details here, 
since this has been most amply illustrated by Ealconer,’^ Owen^ and other writers. 
With regard to the number and succession of the teeth, a short notice is necessary, 
in order that the reader who has not specially studied the dentition of this interest- 
ing group may have no difficulty in following the descriptions given in the sequel. 
It will not he necessary to notice the systems of classification proposed for the 
molars of the Elephantidce, before their homology was thoroughly understood, which 
has been already lucidly done by Dr. Falconer,® and I therefore proceed at once 
to the classification of those teeth as given by the last-named writer. 
In the living Indian elephant, it has been demonstrated that six grinders are 
developed in a horizontally succeeding series, on either side of both upper and lower 
jaws, and that the hinder teeth are more complex than the anterior. The whole of 
these teeth are never in use at any one time, the anterior ones falling out as they are 
worn down, and the posterior ones gradually coming into use and replacing them ; 
the animal when quite adult has only the last molar in use, the length of wear of 
which of course determines the life of its owner. There are never more than three 
teeth on one side of either jaw in use at any one time. 
The Mastodons present a like number of horizontally succeeding teeth. Of 
these six teeth in that group, the thEd, fourth and fifth usually carry the same 
number of ridges, and have hence been termed by Dr. Falconer the “ intermediate” 
molars. In the Trilophodont section of the group the number of ridges on each of 
these three teeth is always three, and in the Tetralophodont, normally four ; the 
tooth (of the horizontal series) immediately in front of the first “ intermediate” 
molar, has always one ridge less than the latter, and tlie tooth behind the third 
“ intermediate” molar, one ridge more than that tooth. The serial position of these 
teeth is, therefore, generally pretty easy to determine, since the three isomerous 
“ intermediate” molars increase regularly in size from the first to the third. 
Of these six teeth, it will subsequently be shown that in many species of 
Mastodons, and in one elephant, the second and third (and sometimes the first) are 
replaced by vertically succeeding teeth, which consequently correspond to the pre- 
molars {dents des remplacement) of the normal mammalian dentition, as exemplified 
in the Pig. The three first teeth in the horizontal Series must therefore correspond 
to the last three teeth of the milk dentition of the Pig, and may therefore be called 
* Pal. Mem., Vol. I, p. 43, et seq. Fauna Antiqua Sivalensis, Pis. I & II. 
- Odontography, p. 613 et seq. 
3 loc. cit. 
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