60—26 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
Mandible. — As it is to great extent on the characters of the mandible that the 
present species is distinguished from the last, it Avill be well to commence with the 
description of that part. It is unfortunate that there is such an element of 
uncertainty as to whether the mandible figured in plate XL really belongs to S. 
giganteus, since there is no doubt of the distinctness of the mandible of the present 
form from that specimen. Putting, however, that specimen on one side, there are 
characters in the mandible, and other remains of the present form, which appear to 
leave but little doubt of its specific distinctness from S. giganteus^ assuming that 
species to be founded on characters of the cranium alone. 
In figure 4 of plate VII. there is represented the cheek-dentition of a portion of 
the right ramus of the inaudible of a large-sized pig collected by Mr. Theobald in the 
Siwaliks of the Potwar district of the Punjab. The four last teeth are still remaining, 
and are in beautiful preservation. In advance of {ImTI there remain the fangs of pm. 3 ; 
the last molar is unworn, the two preceding teetii being in an intermediate condition of 
wear. It will, perhaps, be simplest to commence by contrasting this mandible with 
the one figured in plate XI. In the first place, the molar teeth of the two have a 
somewhat similar general structure, the pattern formed on their worn surfaces being 
a simple one ; but the proportionate size of the three teeth is very different in the 
two. Thus in the present jaw the united length of the three molars exceeds that of 
the corresponding teeth of the other jaw ; the length of mTS is, however, nearly the 
same in the two, though the width of that tooth is greater in the jDresent specimen : 
the smaller proportionate length of m. 3 in the latter is caused by its smaller talon, 
the portion behind a being shorter than that between a and e, while the reverse 
is the case in the other specimen. The first and second molars (m. 1 and m 2) of 
the present jaw are much longer than in the other jaw; their united length being 
greater, instead of less, than that of m73 : the former teeth are also 
proportionately narrower in the present specimen, as is well seen in m. 1 which 
is an elongated tooth, with its length considerably exceeding the width of m. 2, 
as in existing pigs ; whereas in the other jaw the length of this tooth is less than 
the width of m. 2. Precisely similar relations obtain between the length of m. 2 
and the width of the last molar.^ As far as can be judged from the slightly 
different stages of wear of the two specimens, it appears that the columns of m. 3 
are relatively higher in the present specimen (a view of the inner surface of this tooth is 
given in plate VII., fig. 10), Coming to tlie premolars, it will be seen that pm. 4 is a 
relatively smaller tooth than in the jaw figured in plate XI., and has not the great 
lateral expansion at its posterior extremity so characteristic of the latter ; this 
tooth in the jaw under consideration exhibits, however, a large column {a) on the 
inner side, which is not present in existing pigs. The broken base of pm. 3 shows 
1 It may be observed that in many species of Sus, especially those with taller and more complex molars, the first and 
second molars when very much worn become abnormally short, owing to the pressure of the adjacent teeth. As, however, the 
lower teeth represented in pi. XI., and the upper teeth of S. giganteiis represented in fig. 12 of pi. LXXI. of the “ F.A.S.” 
(which have the same proportions as those in pi. XI. of this volume) are in the same stage of wear, which is only a degree 
beyond that of the lower teeth represented in pi. XI., no vitiation of the comparisons can occur from this source. The 
molars of all these specimens retain their original length. 
