ADDITIONAL SIWALIK PERISSODACTYLA AND PROBOSCIDIA. 27 
were sliown to be practically indistinguisliable from pm. 4 of M. angustidens. The 
more worn condition of the second ridge in some of these teeth seems to indicate 
that the serial determination is in those cases correct : but it is quite possible that 
other similar teeth may be milk-molars. Among the specimens obtained by Mr. 
Blanford from Dera Bugti are two very similar teeth of the left side ; one of which 
is well worn, and is represented in pi. IV., fig. 6 ; while the other is almost unworn, 
and is represented in figure 4 of the same plate. The unworn specimen shows the 
two accessory cusj)s (a, h) in the transverse valley; which form a worn disc in the 
other specimen. In the latter the plane of wear of the last ridge is horizontal ; 
while in the specimen figured in the first volume, and in the one in the British 
Museum, this plane inclines towards the anterior ridge : a similar inclination existing 
in the specimen figured in pi. V., fig. 4. It is just possible that this variation may 
indicate specific or serial differences. The transverse valley in the unworn specimen 
appears rather narrower than in the others ; but none of the five teeth present any 
characters by which they can be referred to the present, rather than to the next 
species, or vice versa. There is a certain amount of probability that some of these 
or nearly similar teeth may belong to M. falconeri ; in which case they may be milk- 
molars. The dimensions of the two specimens represented in plate IV. are as 
follows, viz . : — 
A 430. A 431. 
Extreme length . 1’6 1’6 
,, -width i-34 r35 
Height of inner column of first ridge ..... 1‘09 
Mandible. — Among Mr. Blanford’s Dera Bugti specimens there is a fragment of 
the right ramus of the mandible of a mastodon,^ containing m. 2 and m. 3, with their 
crowns hammered off. The base of the crown of the latter tooth precisely resembles 
the last lower molar represented in plate IV., fig. 3, so that there is no doubt that 
the two should be referred to the same species. The length of the tooth in this jaw 
must, however, have been slightly greater than that of the detached specimen. The 
fangs of mTV indicate a tooth similar to the specimen represented in pi. IV., fig. 7, 
but of rather larger size. Below the roots of the molars there is a long cavity, 
filled with matrix, indicating the presence of large incisors. 
From its imperfect condition the mandible, which is broken off a short distance 
in front of m. 2, has not been figured, but it is of considerable importance in 
completing the evidence connecting the specimens already described with M. 
angustidens. As far as its imperfect condition admits of comparison, the Biigti 
mandible agrees precisely with a specimen of the mandible of the latter species 
figured by Kaup,^ and was evidently furnished with a similarly produced symphysis : 
its characteristic points are the straightness of the inferior border, the increase 
of vertical depth at m. 2 as compared with m. 8, and the great lateral compression. 
The vertical depth at m. 3 is 5'85, and at mi 2 6'65 inches: the transverse diameter 
is 4T inches. 
1 Ind. Mus., Ho. A. 435. 
a Kaup, “ Beitrage,” pt. 3, pi I., fig. 1. 
