SIWALIK AND NARBADA PBOBOSCIDIA. 
41—222 
against the summit of a tubercle situated in this valleyd The first ridge is short, 
and has only a very faint trace of a median division ; the second ridge is longer, 
and is distinctly divided into an outer and an inner column by a median cleft ; each 
column of this ridge appears to have been capped by tubercles. The inner one of 
these two columns is placed somewhat in advance of the outer one. The worn 
tubercle in the transverse valley shows that the latter was somewhat blocked at its 
base ; the transverse ridges are of considerable height. 
The length of the tooth is 2’05 inches ; its greatest width 1’5 inches ; and the 
height of tlie worn front ridge 1 inch. 
This tooth is of simpler construction than any of the other molars of Mastodon 
pandionis ; we have, however, seen that in that species the lower molars are less 
complex than the upper, and the anterior lower teetli less complex than the succeed- 
ing ones. In describing the known teeth of Mastodon pandionis in the above quoted 
note in the “ Palseontological Memoirs,”^ Dr. Palconer describes a small tooth of 
that species in the following words : — “ Among the teeth presented (to the India 
House) by Colonel Sykes, there is also a small two-ridged Mastodon tooth, with very 
smooth enamel, which in form, through every detail, agrees so exactly with a speci- 
men (of a lower premolar of Mastodon angustidens) of Lartet’s, that I unhesitatingly 
consider them to be homologous teeth of the same side and of nearly the same age. 
Dimensions of premolar. Lartet’s. Indian. 
Extreme length I'/S 1’9 
Width of front ridge . . I'l 1’15 
Ditto of back ridge 1-4 1’4 
“ Lartet’s specimen is a detached tooth, labelled in his list, ‘Last lower 
molar, left side.’ It consists of two ridges, both of them worn ; but the outer and 
inner discs not continuous, and the middle of the valley occupied by a tubercle, 
which is worn low down, leaving a circular disc. There, is a well-marked anterior 
talon of two worn tubercles, but deeply impressed by an anterior disc of pressure 
against a preceding tooth in position. Behind there is also a talon, but very 
strongly impressed by a disc of pressure, so that the posterior talon only exists on 
the inner side. The crown presents the cucumber shape, so remarked on by De 
Blainville, «.<?., the first ridge is narrow (short), the second broad (long). 
“ The Indian fossil shows precisely the same characters, i.e., two ridges worn, 
and two talons, with a connecting tubercle between the ridges. The back talon is 
marked with a disc of pressure, but the anterior talon consists of two confluent 
prominent tubercles, free from any mark, showing either that there was no penulti- 
mate premolar, or that it was very caducous and dropped out without pressure from 
liehind. The anterior ridge is narrow (short) ; the posterior broad (long), as in 
Lartet’s (specimen) ; but the ridges are more worn, and the discs confluent. The 
crown slopes from the inside, which is higher, to the outside, which is lower, but less 
* This abraded spot is scarcely perceptible in tbe figure, 
2 Vol. I, p. 125. 
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