MOLAR TEETH AND OTHER REMAINS OE MAMMALIA. 
43 
The jaw is very thick at the molar alveoli ; it is curved along the inferior border, 
and is much deeper than the jaw of Camelopardalis giraffa^ but only slightly deeper 
than that of C. sivalensis. The measurements of the specimen are given below in 
the first column, and the corresponding measurements of C. giraffa in the second 
column 
In. 
In. 
Length of fragment 
... 6“0 
Length of first molar 
... ‘l-35 
1-0 
Width of ditto 
... I'O 
0-9 
Length of anterior barrel of second molar 
... 0-8 
0-6 
Depth of jaw at second molar 
... 2-2 
1-6 
Thickness of ditto at ditto 
... 1-5 
1-0 
Camelus sivalensis, Falconer. 
The skull and upper molars of this species have been shortly described by 
Ealconer (“ Fal. vol. J, p. 231) and shown to be close in general structure to 
those of the living camel. 
The upper molars, indeed, of the fossil species, seem to be almost indistin- 
guishable from those of the living species, except by being slightly smaller in size. 
The lower molars, however, of Camelus sivalensis, although exhibiting the same 
simplicity of structure which characterizes the teeth of the family, are readily dis- 
tinguished from those of the living species. 
The inner surface of the lower molars of the fossil species is divided into two 
equal halves by a median vertical ridge or costa ; this ridge is somewhat depressed 
below the general surface of the wall of the tooth, and has a narrow groove on 
either side ; slight oblique ridges bound the anterior and posterior sides of this 
surface. 
In the living camel, on the other hand, the inner surface of the lower molars is 
divided into two portions by a very shallow and broad groove, without any trace of 
the median ridge ; the anterior and posterior bounding ridges are also much less 
strongly marked than in the fossil species, so that the whole of the inner surface of 
the tooth is nearly flat. 
At the antero-external angle of the first barrel of the lower molars of Camelus 
sivalensis there is a prominent vertical ridge, not found in the teeth of the living 
species. This ridge may be seen in the figure of the lower molars of the Siwalik 
camel given in the “Eauna Antiqua Sivalensis,” {Flafe S7,Jig. 5) ; a similar ridge 
occurs in the lower molars of the American Auchenia (Owen’s “ Odontography^' 
vol. J, p. 686), by which they are distinguished from those of the old-world 
camels. The slenderness of the jaw of the Siwalik camel is also an approacli to the 
form of that of Amhenia ; none of the specimens of the fossil species exhibit the 
relationship of the premaxillse to the nasals ; it will be interesting to note, if more 
perfect specimens subsequently are found, whether the premaxillse were separated 
( 61 ) 
