SIWALIK AND NARBADA PROBOSCIDIA. 
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of each ridge, but these trefoils are nearly always less distinct in the European teeth, 
and in some are very imperfect. In most of the teeth of M. angusticlens, the accessory 
columns are more developed than in M. falconeri, and the valleys are consequently 
blocked to a greater extent. The second true molar of the former species carries 
a greater number of cusps on its ridges, and its talons are more complex than in 
the corresponding tooth of the latter. Again, the true molars of the European 
species generally diminish in width anteriorly to a greater extent than do those of 
the Indian species. 
Comparing the tooth represented in fig. 8 of Plate XL of the Eauna Anti- 
qua Sivalensis,” described as being the first upper true molar of Mastodon angus- 
tidens, but which is of the same size as the second true molar represented in the 
next figure, with the second upper true molar of Jf. falconeri described above, we 
find that the former tooth is somewhat longer than the latter, and is wider posteri- 
orly and narrower anteriorly. The valleys in the European tooth are more blocked, 
owing to the greater development of the accessory columns ; the latter being placed 
on the line of the median cleft, instead of on one side of it, as in M. falconeri. 
Again, the ridges of the molar of M. angustidens are considerably higher than are 
those of M. falconeri : thus, the height of the last ridge in the so-called first lower 
molar of the former species is 2-2 inches, whereas in the nearly equal-sized tooth 
of the latter it is only 1*4 inches. In an undoubted first lower true molar of M'. 
angustidens in the collection of the Indian Museum, which is less than 3 inches 
in length, the height of the ridges is equal to the height of those of the corre- 
sponding tooth of M. falconeri with a length of 4’1 inches. 
A second upper true molar of Mastodon angustidens represented in fig. 3 of 
Plate III of the second volume of the “ Palaeontological Memoirs,” makes a nearer 
approach to the corresponding tooth of M. falconeri than does any other tooth that 
I have seen. The ridges on that tooth, however, are higher, the talons less develop- 
ed, the accessory columns larger, and placed nearer the median cleft, than in M. 
falconeri. An excellent figure of what seems to be the first upper true molar of M. 
angustidens is given by H. von Meyer L that specimen is a regularly oblong tooth, 
and has the columns of the ridges more distinct, and a deeper mesial cleft than in 
the last milk-molar of M. falconeri (Plate XXXII, fig. 3) : the European tooth 
has a lateral cingulum continuous with the fore-and-aft talons, which is entirely 
wanting in the Indian tooth ; in the latter the valleys are less open and more 
sinuous than in the former. 
The presence of a cingulum in the upper molars of M. angustidens seems from 
von Meyer’s figures to be very constant. The specimen of an apparently second 
upper true molar figured in the above quoted plate (fig. 7) of von Meyer’s, has an 
almost complete cingulum, which is entirely wanting in the corresponding tooth of 
M. falconeri (Plate XXII, fig. 1) : in the former tooth the valleys are less entirely 
open than in the latter : other teeth figured by von Meyer exhibit corresponding 
differences from those of M. falconeri, which the reader can examine for himself, 
’ Palseontographica, Vol, XVII, Piate III, fig. 1, (the lowest tooth in the figure). 
H 
