64-2 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
The first true molar, as usual, carries three ridges, and is oblong in form ; the 
second carries two ridges, and approximates more nearly to a square. In the follow- 
ing table the dimensions of this mandible are compared with the corresponding 
dimensions of a cast of the Eppelslieim skull of D. giganteum : — 
Indian. European. 
Depth of mandible at last premolar ...... 10' 8 8'0 
„ „ second true, molar 7'5 6’3 
Width of „ „ 7-1 5-5 
Interval between base of molars and foramen of mandibular nerve . 4'1 2'9 
Length of 1st true molar » . 3'9 3'5 
Width of „ „ . 27 2'65 
Length of 2nd ,, . . 3'9 3 55 
Width of „ 3 '4 3'3 
Erom these measurements it will be seen that the Perim jaw is altogether of 
larger dimensions than the European, and further, that in the former the propor- 
tionate increase of depth near the symphysis is greater than in the latter. In all 
respects the jaw agrees precisely with the fragment of the left side described by 
Dr. Ealconer from Perim Island, 1 and the new jaw, therefore, undoubtedly belongs 
to the same species. The whole jaw is deeper and thicker than in D. giganteum , 
and thereby, as was pointed out by Dr Eaconer, “ approaches very closely the mas- 
sive and turgid form seen in the typical mastodons.” 
With regard to the molars, it will be seen that in the Indian species the true 
molars are longer in proportion to their breadth than in the European species. The 
tooth from Sind, figured and described in the first volume, 2 agrees precisely, both in 
dimensions and form, with the first true molar of the Perim specimen. Hence we may 
infer, firstly, that the reference of the Sind tooth to D. indicum was correct ; and, 
secondly, that the proportion of the antero-posterior and transverse axes of the first 
true molar is constant, and affords an important distinction between the Indian and 
European species. 
Einally, the examination of this jaw from Perim Island strongly confirms 
the conclusion arrived at in the first volume as to the existence of three Indian 
species of Dinotherium , distinct from their European congeners. 
Mastodon pandionis, Ealconer. 
Mandibles. — Three specimens of mandibles of mastodons have come under my 
notice since the publication of the first volume, two of which certainly, and the third 
probably, may be referred to this species. 
JPerim Island specimen. — The first specimen is another from the Bombay 
Asiatic Society’s collection, and has been already alluded to in the ‘ Records.’ 3 The 
fragment consists of the greater portion of the right ramus of the mandible, contain- 
ing two molars. They each contain three ridges and a hind talon, and from their 
1 ‘ Pal. Mem.,’ Vol. 1, p. 404. * PI. XXXI, fig. 2, p. 194. 3 Loe. cit. 
