SIWALIK AND NARBADA PROBOSCIDIA. 
73-254 
originally carried on the crown cannot now be determined. The figured tooth 
carries six transverse ridges and small fore-and-aft talons ; its ridges are divided by 
a medhm cleft into inner and outer columns. Accessory columns are present in the 
valleys. When worn down, the columns would present irregularly shaped discs 
of dentine on their summits, and not trefoils (the preceding molar in the palate 
shows these irregular discs). As before said, the columns are not arranged in our 
specimen in nearly so alternate a manner as in Balconer’s specimens of the last 
upper molar of M. sivalensis ; it will, however, be seen from other teeth figured 
in the “ Eauna Antiqua Sivalensis” (and also from the specimens in the Indian 
Museum), that there is considerable variation in this respect, as also in the number 
of accessory tubercles. In consequence of this different arrangement of the columns 
of the ridges in our specimen and Ealconer’s specimens, the valleys are much less 
blocked in the former than in the latter. 
The last upper molar of the species may, therefore, carry either five or six 
ridges. 
Third lower true molar. — Specimens of the third lower true molar of M. sivalensis 
are represented in the “Eauna Antiqua Sivalensis” (Plate XXXV, fig. 1, Plate 
XXXVII, figs. 7 and 8), aU of which carry six ridges and a hind-talon. The 
ridges are disposed alternately, and a few accessory tubercles, which may vary 
in number, are present in the valleys. The specimen represented in fig. 8 of 
the latter plate has a length of 8'8 inches and a width of 2’9 inches. 
In fig. 3 of Plate XLIV of this memoir, a tooth is figured, which is implant- 
ed in a nearly complete, though somewhat crushed mandible, which was collected 
by Mr. Theobald in the Punjab. This tooth, though differing in the number of 
ridges from Ealconer’s specimens, seems probably to be the last lower molar of 
M. sivalensis. The figured tooth is from the right ramus of the mandible, and as 
it is well worn and has no tooth succeeding it from behind, must be the last of 
the series. 
This tooth carries five ridges and a very small hind-talon. The last ridge is the 
smallest. This last ridge consists of a very distinct inner and outer column, separ- 
ated by a median cleft. The worn summit of each column presents an irregularly shap- 
ed and depressed islet of dentine. The columns have only a very slight alternate 
arrangement. In each valley there is a cluster of accessory tubercles, which are 
in general attached to the preceding ridge. The first valley has four tubercles, the 
second three, the third two, and the fourth one. 
If this tooth be compared with the corresponding tooth of Mastodon pandionis 
represented in fig. 4 of Plate XXXV, it will be seen, as already noticed, that the two 
are almost identical in form, if the large talon in the latter be counted as a fifth 
ridge ; and indeed if the two teeth had been found detached, they would almost cer- 
tainly have been referred to the same species. It will, however, be remembered that 
the tooth of M, pandionis was implanted in a fragment of the mandible to which 
belonged the enormous symphysis represented in fig. 1 of Plate XXXVI. The figured 
