I DESCRIPTION OF THE SIVATHERIUM, 



same form and character as in the ox : to have been intimately united with 

 the occipitals, and to have joined with the frontal at the upper angle 

 of the skull. 



The form and characters of the occipital are very marked. It occu- 

 pies a large space, having width proportioned to that of the frontal, and 

 considerable height. It is expanded laterally into two alse, which com- 

 mence at the upper margin of the foramen magnum and proceed upwards 

 and outwards. These alee are smooth, and are hollowed out downwards and 

 outwards from near the condyles towards the mastoid region of the tem- 

 poral. Their inner or axine margins proceed in a ridge arising from the 

 border of the occipital foramen, diverging from each other nearly at right 

 angles, and enclose a large triangular fossa into which they descend 

 abruptly. This fossa, is chiefly occupied by stone in the fossil, but it does 

 not appear shallow, and seems a modification of the same structure as in 

 the Elephant. There is no appearance of an occipital crest or protube- 

 rance. The bone is mutilated at the sides towards the junction with the 

 temporals. Both here and at its upper fractured margin its structure is ~ 

 seen to be formed of large cells with the diploe expanded into plates, and 

 the outer and inner laminae wide apart. This character is very marked 

 at its upper margin, where its cells appear to join on with those of the 

 frontal. The condyles are very large and fortunately very perfect in the 

 fossil, the longest diameter of each is 4.4 inches, and the distance measured, 

 across the foramen magnum, from their outer angles, is 7.4 inches : dimen- 

 sions exceeding those of the Elephant. Their form is exactly as in the 

 Raminantia, viz. their outer surface composed of two convexities meeting 

 at a rounded angle : one in the line of the long axis stretching obliquely 

 backwards from the anterior border of the foramen magnum ; on the other 

 forwards and upwards from the posterior margin, their line of commissure 

 being in the direction of the transverse diameter of the foramen. The lat- 

 ter is also of large size, its antero-posterior diameter being 2.3 inches, and 

 the transverse diameter 2.6 inches. The large dimensions of the foramen 



