254 MR. BUSK ON THE REMAINS OF 
entirely in the appearance of the surface of the bone, with that of a young African 
Elephant in the British Museum, in which specimen all the bones of the cranium and 
face are perfectly separate; and in the lower jaw the 3rd molar is in full wear, no 
vestiges remaining of the 2nd molar. ‘The dimensions of the two bones are as under :— 
Tanue I.—Measurements* of Exoccipital Bone, in Maltese and African Elephants. 
| Width be- | Teeth 
| . Greatest 
Height or | tween bor- | Length |yw; ~ | Thickness x 
teeta ‘Breadth of] ders of ok of basioadi-| Wath of b a | in region of condy- | width of 
leneth of lexoccipital.| dyloid fossa | pital syn- lear I d SYD- | of mastoid | 1oid arti- | condyloid 
Baek arate Be x foramen |chondrosis. chondrosis |" cells, | Cularsur- | articular 
De Se ee face. surface. 
agnum. 
Young African Ele- = an | Al Br | 
= cf 35 16 19 “95 1:3 PH teal hie 1163} 
phant, No. 708, B.M. 22 | 2 
Young Maltese fossil) 4:7 | 39 1-6 feGiean|e aloe 19 2°35 1:55 
It will thus be seen that in general dimensions and proportions the two bones 
are remarkably alike; but they present certain differences, which would appear, as I 
think, clearly to indicate that they belong to different species. 
In the first place, notwithstanding the apparent similarity of age, it will be observed 
that the fossil is very much thicker in the part occupied by the paramastoid cells, and 
that the proportions of the condyloid articular surface are not the same. But the most 
striking distinction consists in the circumstance that, in the African Elephant, the 
cerebellar fossa is very concave or deep, and that the sulcus for the lateral sinus is also 
very deep, and separated from the opening of the paramastoid cells by a sort of vertical 
wall; whilst in the Maltese fossil the cerebellar fossa is only slightly hollowed, and 
there is scarcely any trace of a sulcus for the lateral sinus. And in another very 
young (or perhaps foetal) cranium of the African Elephant (No. 7087, B.M.), in an 
exoccipital having a greatest diameter of 37-1, and least of 2”-9, the sulcus for the 
lateral sinus is quite as well marked as in the above,—whence it may be concluded 
that this character is not dependent upon age, and may probably be relied upon as 
indicating a distinction between the Maltese form and £. africanus. I have not 
had an opportunity of comparing the exoccipital of the Indian Elephant of the same 
age. In the young African Elephant the opening into the paramastoid cells is tri- 
angular, and a transverse septum may be observed within, dividing the main cavity 
into two primary loculaments, of which the posterior is shallow, and the anterior very 
deep, communicating at the bottom with two deeper cells. In the Maltese fossil the 
same primary division into two chambers is observable; but the slender trabecular 
septum between them is absent, and replaced simply by an angular ridge. It should be re- 
marked in addition, that in the African species the concavity or sulcus above the 
condyle is much deeper than in the Maltese, and that the curve of that part of the 
foramen magnum which is formed by the exoccipital is different in the two cases. 
* Throughout this paper the measures are given in inches and tenths. 
