251-70 
SIWALIK AND NAEBADA PROBOSCIDIA. 
It is probable tliat the third milk-molar figured here belonged to a female, 
while the specimen figured in the “Fauna Antiqua Sivalensis” belonged to a male 
animal. 
In the jaw in which the figured third upper milk-molar is implanted there are 
no traces of any premolar, either above that tooth, or having replaced 'the second 
milk-molar, which has fallen out ; from this we may conclude that premolars were 
not developed in Mastodon sivalensis. 
The serial position of the figured third upper milk-molar is of considerable 
importance, as from it we are enabled to determine the position of some other teeth, 
and I will therefore recapitulate the grounds upon which its position is fixed. The 
figured tooth corresponds exactly in form with the larger tooth represented in fig. 
2 of Plate XXXVI of the “Fauna Antiqua Sivalensis,” which again has in front of 
it a tooth of such a large size that it must be the second milk-molar ; hence the 
larger tooth must be the third of that series. 
The third upper milk-molar figured here has behind it three ridges of a larger 
tooth, which must consequently be the first true molar, to which we shaU have to 
refer again. 
Third lower milk-molar. — The tooth represented in fig. 2 of Plate XLIV is im- 
planted in a fragment of the right ramus of the mandible, and was obtained by Mr. 
Theobald in the Siwaliks of the Kangra district. As it is larger and contains one 
ridge more than the above noticed second lower milk-molar figured in the “ Fauna 
Antiqua Sivalensis,” it must be the third lower milk-molar, or the corresponding 
lower tooth to the third upper milk- molar, represented in fig. 2 of Plate XLI. 
The last ridge of this tooth has been somewhat damaged, and the posterior talon com- 
pletely broken away. The crown is long and narrow, with the outer border concave 
and the inner convex. The inner extremity of each ridge is considerably higher 
than the outer. Each of the three ridges which are uninjured are worn, and exhi- 
bit irregularly shaped hollows of dentine. The ridges are of considerable relative 
height, and each is mesially divided by the cleft traversing the longitudinal axis 
of the crown into an inner and an outer column. These columns are arranged 
alternately so that each ridge is set obliquely to the long axis of the crown, in such 
a manner that its inner column is considerably in advance of its outer column. Bv 
this arrangement, aided by the presence of some outlying tubercles, the transverse 
valleys are completely blocked. The length of this tooth is 3*4 inches, and its 
greatest width 1’8 inches. The height of the somewhat worn penultimate ridge is 
1-3 inches. In fig. 3 of Plate XXXVII of the “ Fauna Antiqua Sivalensis,” 
there is figured a worn third lower milk-molar of M. sivalensis which seems to have 
carried four ridges, and which, as regards form and size, agrees almost exactly with 
the specimen figured here. 
Ridge -formula of the milk-molars . — From the specimens of milk-molars figured 
here and in the “ Fauna Antiqua Sivalensis,” the serial positions of which are fixed 
beyond the possibility of doubt, it is quite clear that these teeth always follow the 
