1 ^ 47—66 
SIWALIK AND NARBADA PEOBOSCIDIA 
General cliaraeters and Summarizing what is known regarding this 
species, we find that, as far as we are at present acquainted with it, the dentition 
follows the normal tetralophodont law in respect to the number of ridges carried on 
the crowns of the molars. Premolars were developed in the upper jaw, and, therefore, 
probably also in the lower ; the mandible is produced into a trough-like symphysis, 
intermediate in length between that of the living Indian elephant and that of M- 
pandionis ; it was furnished with incisors in some individuals, which were wanting in 
others. The molars carry tall ridges, of which the columns develope accessory tubercles 
blocking the transverse valleys ; one of the columns of each of the anterior ridges 
when worn down, presents on its summit a trefoil-shaped islet of dentine. Cement is 
present in small quantity in the valleys. The characters of the cranium have already 
been pointed out. 
In the form of its molars this species approaches nearest to the European 
M. longirostris, but is at once distinguished by the form of the mandible and by 
certain characters of the molars already pointed out. 
The molars of the tetralophodont Mastodon dissimilis of Jourdan,^ from the 
upper Pliocene of the Ehone valley, are of the type of those of M. perimensis, but. 
as is well shown in the last upper molar, the ridges have a greater tendency to an 
alternate arrangement of their columns and show less distinct trefoils of dentine, than 
in M. perimensis. The last upper molar of the European species is more oblong in 
form than that of the Indian, not contracting posteriorly as the latter does, and the 
hind-talon consequently being of greater relative width. Other smaller differences 
in the teeth of the two species will be seen on comparing the figures. There are no 
figures of the cranium or of the complete lower jaw of M. dissimilis given in the plates 
quoted 'in the note. 
It will probably have struck the reader that in regard to the shape of the 
ridges, the molars of M. perimensis present a striking resemblance to those of M. 
falconeri, the two being, however,. broadly distinguished by the one having a tetra- 
lophodont, and the other a trilophodont arrangement of the ridges in the interme- 
diate molars. The two species, as far as I can judge from the broken mandible of 
M. falconeri, are further distinguished hy the form of the mandible, which is more 
convex interiorly and thicker in M. falconeri ; in the latter species there are no 
premolars and no cement, both of which occur in the other species. It is unfortu- 
nate that I have not been able to trace M. perimensis through its milk-molar 
dentition, and it might be argued from this that both species had trilophodont milk- 
molars, and both tri-and tetralophodont true molars. Apart, however, from the 
important distinctions already pointed out, the last milk-molar of M. falconeri 
(Plate XXXII, fig. 3) (which is exactly like the first true molar in the same young 
’ Lortet and Chantre : “Mastodontes du Bassin du Rhone.” Archiv. du Mus. d’Hist. Nat. de Lyons, Vol. II, 
Pis. I-VII Lyons, 1878. Only the plates of the molars of this species have yet reached India, the letter-press being 
in a succeeding number. 
