CRANIA OP RUMINANTS PROM THE INDIAN TERTIARIES. 19—106 
the lower borders of the horn-cores ; consequently the interval between the ex- 
tremities of the temporal fossae is far larger than that between the external angles 
of the condyles ; the same interval also is considerably less than that between the 
lower border of the foramen magnum and the summit of the occipital crest, and is 
equal to more than half the width of the widest part of the occiput. There is no 
marked prominence below the occipital crest for the attachment of the ligamentum 
nuchae; and the supra-cristal portion of the occiput considerably overhangs the 
infra-cristal portion; the intercornual ridge is slightly arcuated. Pinally, as a 
character of minor value, the directions of the horn-cores are quite different ; those of 
Bos namadicus have a graceful yery open cmwe, the first tmn of which has the 
superior border convex ; in Bibos the horn-cores have but one slight curve, and their 
upper border is concave. The anterior border of the orbits in Bos namadicus is very 
nearly parallel with the long axis of the cranium, and the axis of the orbit is directed 
outwards ; in Bibos the same border of the orbit is placed obliquely to the long axis of 
the cranium, and the axis of the orbit is directed downwards and outwards. There 
can therefore be no doubt as to the distinctness of the Nerbudda ox from the genus 
Bibos. In one point, however, the cranium of Bos namadicus differs from those of 
more typical species of the genus, and thereby approaches to the cranium of Bibos ; 
this point is the relation of the premaxillse to the other bones of the face. In his 
definition of the restricted genus Bos, as given in the first Catalogue of the TJngulata 
in the British Museum {1853), the late Dr. Gray says that the premaxillse are large 
and always extend upwards into the triangular space between the maxillge and the 
nasals, and consequently articulate with both these bones, in the same manner as in 
the genus Bubalus ; in the genus Bibos, on the other hand, the premaxillse are small, 
and are attached only to the distal extremities of the maxillge, and are separated by 
a considerable interval from the nasals. In the second Catalogue of Ruminants in 
the British Museum {1873), however. Dr. Gray has added a new species of Bos, 
namely, the Bos chmensis of Mr. Swinhoe, which vitiates the above distinction 
between Bos and Bibos, though no mention of this fact is made in the Catalogue. 
We may refer to a figure of the cranium of the Chinese species, which is undoubt- 
edly a true Bos, given in the Proceedings of the Zoological Society of London for 
1870, and we shall then find that the premaxillae are small, and do not extend uj)- 
wards to the nasals, precisely as in Bibos. 
In our figured cranium of Bos namadicus, the distal portion of the face has 
been in great part broken away, so that the relations of the different bones cannot be 
well observed ; on the right side of the specimen, however, a minute portion of the 
proximal extremity of the premaxilla still remains ; this is situated near the ex- 
tremity of the maxilla, and is far removed from the nasals, precisely as in Bos chmensis 
and in Bibos ; other less complete specimens of the cranium of Bos namadicus in 
the Indian Museum show this relation more clearly. The above facts, therefore, 
compel us to abandon one of Dr. Gray’s distinctions between Bos and Bibos as not 
being applicable to all the species. It is noteworthy that the short premaxillge 
