44 
Records of the Geological Survey of India. 
[vOL. xn. 
molar is unfortunately broken away, but from tbe small size of its base, I imagine 
that it could only have canned three ridges. The last molar has a very deep 
longitudinal valley, which divides each transverse ridge into a distinct outer and 
inner column; large accessory columns ai’e placed in the valleys, which are in 
consequence completely blocked. The disks of wear of the columns form 
irregular circles ; the tooth has some resemblance to some varieties of the molars 
of M. sivalensis, in which the alternate arrangement of the columns is less pro¬ 
nounced than usual; the last molar of the latter has, however, five or six ridges. 
When complete, the distal extremity of the mandible must have been at least 30 
inches in advance of the last molar. 
There are no tusks in this specimen; among Mr. Theobald’s collection, 
however, there is the distal extremity of an elongated mandibular symphysis of a 
species of Mastodon, which cari’ies portions of two veiy large tusks. This 
mandibular rostrum cannot belong to any of the described species of Siwalik 
Mastodon; and as it agrees in fonn with the last specimen, I consider it probable 
that both belonged to the same species; the tusked jaw being that of a male, and 
the tiiskloss that of a female individual. The fragments of tusks remaining in 
the specimen are only some 10 inches in length; they are much compressed 
laterally, the transverse section being pear-shaped, having the thinner end up¬ 
wards. The inferior border of the fragments is convex, and the superior border 
concave; the vertical diameter is 3’2 inches, and the transverse diameter at the 
thickest part I'll inches. 
Another specimen of the mandible of a trilophodont Mastodon broken off at 
the symphysis, carries two molars, which are respectively the penultimate and last. 
The second of these teeth agrees precisely with the corresponding tooth of the 
last specimen of the mandible, but being loss worn, is more suitable for descrip¬ 
tion ; the identity of these teeth shows that the two mandibles belonged to the 
same species. The penultimate tooth in the second mandible carries three ridges 
and a hind talon, which proves that the first jaw belongs to a Trilophodon. In 
these teeth each ridge is divided by a longitudinal channel into an inner and an 
outer column; each outer column gives off an accessory column from either side, 
which together project obliquely into and quite block the transverse valleys. 
The whole arrangement of the columns on the outer side form a zigzag arrange¬ 
ment ; while the summit of each column wears into a circle. 
Now, the only two known Indian trilophodons are M. falconeri and M. 
paiulionis; the molars of the former I have not yet been able to describe. The 
penultimate lower molar of that species is, however, much larger than the same 
tooth in our new specimens, and has nearly open valleys, with distinct and clear 
ridges, whose summits wear into trefoils and not into circles. I shall hope 
shortly to be able to show by a figure the complete distinctness of these two 
teeth. The jaws of the two are further very different—that of M. falconeri 
being thick and rounded, while the present specimens are thin and flat. 
Of M. pandiotiis a description of the penultimate upper molar will be found 
at page 124 of the first volume of the “ Palseontological Memoirs of Dr. Fal- 
