SIWALIK AND NARBADA PROBOSCIDIA. 
63—234 
almost assuming the proportions of a fifth ridge. Each ridge is very low and blunt 
and closely approximated to the adjoining ridges. A longitudinal cleft, placed 
slightly on the outer side of the median line of the tooth, divides each transverse 
ridge into an inner and an outer column, each of which is again suh-divided into 
smaller mammillae or cusps, of which there are generally two on the outer, and four 
on the inner column. The transverse valleys are perfectly uninterrupted, except 
at the inner extremities of the third and fourth, where there are low and blunt 
tubercles. There are semi-distinct tubercles on the hinder side of the latter ridges. 
The tooth agrees in all essential characters with the milk-molars already described. 
In the first column of the following table are given the dimensions of the 
palate to which the figured tooth belongs, while in the second column are given 
those of the somewhat larger but very similar palate referred to above : — 
Interval between outer surfaces of posterior extremeties of second molars . 
10-0 
ll-O 
Ditto ditto of anterior 
ditto 
ditto 
8-0 
9-0 
Ditto inner surfaces of posterior extremeties of second molars . 
3-4 
4-0 
Ditto ditto of anterior 
ditto 
ditto 
1-5 
2‘4 
Length of second molar 
6-6 
6-3 
Greatest width of second molar 
3-6 
4-0 
Width of first ridge of third molar . 
4-1 
4-3 
The second upper molar in the larger palate differs f]’om the figured specimen 
of the same tooth, in that its posterior talon is of very small size, and makes 
no approach to a fifth ridge. In fig. I of Plate XXXVIII an imperfect second 
upper molar of M. latidens is represented, which in the form of its ridges and valleys 
wull he seen to correspond precisely with the second upper molar represented in 
fig. 2 of the same plate. Both teeth are from the right side of the upper jaw, 
and both are very evidently in the same state of detrition. The imperfect tooth, 
wdiich was collected by Mr. Theobald in the Punjab, has lost a part of its first 
ridge and anterior talon, and also a portion of the inner extremeties of the second 
and third ridges. This tooth is of slightly smaller size than the complete specimen, 
but is doubtless the corresponding tooth. In describing the perfect tooth repre- 
sented in fig. 2, it was noticed that there might he some question in deciding whether 
that tooth had five ridges, or four ridges and a large hind-talon. The imperfect 
footh has, however, most distinctly five ridges, though the fifth is somewhat smaller 
and lower than the others : at the hack of this fifth ridge there is a very small 
hind-talon. Now, there can he no doubt but that this fifth ridge is the represent- 
ative of the talon of the more perfect tooth (fig. 2), and we have, therefore, 
established the important fact that in the second upper molar of this species there 
is a complete transition from a foim-ridged to a five-ridged tooth. 
Second lower true molar . — Of the second lower true molar there are several 
specimens in the collection of the Indian Museum. In their general characters 
these teeth are merely enlarged repetitions of the lower milk-molars represented in 
figs. 1 and 2 of Plate XXXVII, and I have not, therefore, thought it necessary to 
give figures of any of them. Some of these teeth carry four -transverse ridges 
