part!.] L/jde/d'e?: Pui-lJter Notices of Siwalil'Mammaliu. 37 
tLe relative lerigtli of the last molar, we find that the fossil agrees most closely 
with the chimpanzee and man, in both of which this tooth is much shorter than 
either of the other true molars. In the orang there is a very slight difference 
between the lengths of the first and the third true molars ; in the gorilla, on the 
other hand, the last molar is much larger than the first. This difference in the 
relative lengths of the first and last molars in the gorilla, and the Siwalik jaw, 
together with the difference which we have already seen to obtain between the 
last premolars of the same, renders it evident that there is no great affinity 
between these two, and makes it unnecessary to carry our comparisons any further 
in this direction. 
Comparing the dimensions of the molars of the fossil jaw with those of the 
female orang, we' find that the true molars of the former are larger than those 
of the latter, and that the united length of the true molars is also greater. When, 
however, we bike the whole molar series, we find that the five teeth of the female 
orang have an absolutely greater united length than the same five teeth in the 
Siwalik jaw, this being of course due to the small size of the premolars in the 
latter. In the chimpanzee, the length of the united molar series is less than in 
the Siwalik jaw, but the united length of the two premolars is greater, while the 
length of the three true molars is less: the projiortions in the human jaw arc in 
this respect nearest to the fossil. 
Again, in the width (transverse diameter) of the base of the outer incisor, the 
fossil jaw is closer to man than to any of the large apes. In man there is no 
diastema between the canine and the incisor; in the orang this diastema is 
larger than in the chimpanzee, which in this respect approaches man. In the 
fossil jaw this diastema is very slightly larger than in the orang. 
The dimensions of the base of the canine are considerably stouter in the 
fossil jaw than in either the female orang or the male chimpanzee, and approach 
those of the male orang and gorilla; though the shortness of the crown proves, 
as we said, that our specimen belongs to a female. In the female orang there is 
a disk of wear on the posterior border of the canine, which does not occur in the 
fossil specimen. 
The following summary exhibits the points of resemblance and difference 
between the fossil jaw and the jaws of man, the hhimpanzee, and the orang, 
which are the only three species which are closely related to it:— 
Man. 
Resemblances .— Shortness of premolars; small size of last molar ami of incisor. 
Differences .—line of teeth; large canine and diastema. 
Chimpanzee. 
Resemblances .—Straight line of teeth ; shortness of premolars in a less degree; small size of 
last molar; large canine and diastema. 
Diff'e/’ences.—SmaW incisor. 
