227—46 
SIWALIK AND NATLBADA PROBOSCIDIA. 
the other, and that the columns are rather more perpendicular in M. pandionis. 
The two teeth are, however, so alike that it appears to me to he extremely 
doubtful if they could he distinguished as belonging to separate species, if they had 
been found detached from the jaws. The tooth of M. pcmdionis, it will he remem- 
bered, is implanted in the ramus of the mandible with the long spout-like rostrum 
figured in Plate XXXVI, fig. 1, and as we find from other specimens, was preceded 
by a three-ridged tooth. The tooth of M. sivalensis, on the other hand, belongs 
to a nearly complete mandible with a short symphysis (described below), like that 
of the living Indian elephant, and was preceded by a four- (or occasionally five-) ridged 
tooth. There can, therefore, he no question as to the specific distinctness of the 
animals to which the teeth belonged. Prom this we learn that certain of the teeth 
of some species of Prohoscidia may be almost indistinguishable from those of 
a totally distinct species, and from this it is not a very long step to the whole of the 
teeth in two species being of the same character, though the crania and mandibles 
are very distinct : this has an important bearing on the case of §tegodon insignis 
and 8. ganesa, to be noticed below. I ought to add that the molar of M. siva- 
lensis has no traces of the cement which occurs in that of M. pandionis. 
Distribution. — Bemains of Mastodon pcmdionis in the collection of the Indian 
Museum, have been obtained from the Siwahks of the Western Punjab, Sind, and 
Perim Island : according to Dr. Falconer they have also been obtained from the 
Deccan, whence molars were sent by the late Colonel Sykes. As no remains of this 
species were obtained by Cautley and Falconer among their immense collections of 
fossils from the more easterly Siwaliks, it seems probable, as in the case of the last 
described species, that the geographical range of M. pandionis did not extend 
much to the eastward of the Jhelum river. The second milk-molar figured in 
the F. A. S. and referred above provisionally to this species, is an apparent excepi- 
tion ; there is, however, no record of the locality whence that specimen came. 
Section B. — Tetralophodon, Falconer. 
Intermediate molars normally with four, but in some species occasionally with 
five , transverse ridges. 
Species 3 : Mastodon latidens. Clift, {in parte.) Plates XXXVII, XXXVIII, 
& XXXIX. 
History. — This species of tetralophodont Mastodon was originally named and 
described by the late Mr. Clift upon the evidence of certain molars brought from 
the valley of the upper Irawadi by the late Mr. Crawfurd early in the century.' 
These fossils appear to have been the first winch were obtained by Europeans 
* Trans. Geol. Soc. Lon., Ser. 2, Vol. II, p. 369, 
