THREE EXTINCT SPECIES OF ELEPHANT. 275 
is broken off immediately behind the condyle, their respective breadths across the con- 
stricted part admit of fair comparison. Compared in this way, fig. 42/ measures in 
extreme height 1°95, and at the constricted part above the condyle 0:9; whilst fie. 
44 in the corresponding directions measures 17-85, and 1-1. It is true that the latter 
isa little more worn on the upper edge; but, making every allowance for this, it is un- 
doubtedly the wider of the two in the antero-posterior direction. Again, in fig. 42’ the 
condyloid articular facet measures 1” x 0”:5, and in No. 441105. And in No. 42’ 
the surface of the exo-basioccipital synchondrosis is 0:6 x 0:3, and in No. 44 0-6 x 0-4. 
But, besides these differences in measurements, which in such small dimensions are not 
so inconsiderable as they may seem, the two bones present others, as it appears 
to me, of even greater importance. In the first place, on the inner aspect of No. 42! 
(42' a) the cerebellar fossa is much more concave, and the sulcus for the lateral sinus 
much more pronounced; whilst in 44 @ the cerebellar fossa is but slightly concave, 
and no discernible trace of the lateral sulcus can be perceived. In consequence of 
this difference in the internal aspect, the opening of the paramastoid cells (p c), m 
fig. 42’ a, is separated, as it were, from the cerebellar fossa, or rather from the lateral 
sulcus, by a steep or abrupt wall, which is wholly wanting in 44a. On the outer aspect 
the chief thing remarkable is the greater flatness of the surface. ‘The anterior margin 
immediately above the exo-basioccipital synchondrosis, or at the part where it forms the 
posterior boundary of the jugular foramen (j f') (the jugular sulcus, as it is termed in 
human anatomy), is very acute in both specimens; but the bone itself, immediately beyond 
the border, is very much thicker in 44, And this difference is so great upon viewing 
the bones edgeways, though not readily described in words, as of itself to give a different 
character to the two bones when viewed in this aspect. I am moreover particularly 
desirous of directing attention to this part of the bone, inasmuch as it is here that a 
very important difference exists between the exoccipital of the Indian and that of the 
African Elephant at the same age as the Maltese specimens. And it fortunately happens 
that we have the materials for comparison in the British Museum and Royal College 
of Surgeons, the former affording the cranial bones of an African, and the latter that 
of an Indian Elephant, of apparently the same age as the Maltese bones we are discuss- 
ing. Comparison of these shows that, whilst at first sight they more closely correspond 
than might have been anticipated, in many respects they differ to about the same extent 
as the two Maltese specimens. Amongst these differences the most striking is the form 
of the anterior border at the jugular sulcus: in the African this border is very thick 
and rounded, whilst in the Indian it is thin and acute. And, as might be supposed, there 
is to some extent a corresponding difference in the depth of the lateral sulcus, and the 
general concavity of the cerebellar fossa, both of which are considerably greater in the 
Indian than in the African, though perhaps not to the same extent as in the two 
Maltese exoccipitals. On the same aspect also there may be observed in No. 44 two 
ridges close behind the edge of the jugular sulcus, where in No. 42’ the surface is 
