AND VARIOUS OTHER BONES OF THE MASTODON. 39 



Os humeri of right side. 



Scaphoides, lunare, cuneiform and unciform of right carpus. 



Os femoris, tibia, and os calcis of right side. 



Radius and ulna of left side. 



Tibia, fibula, and patella of left side. 



Os calcis, astragalus, scaphoides and cuboides of left tarsus. 



Conformation of Head. 



The occipital bone (see Plate I., fig. 1,) forms a plane, looking backwards and 

 Upwards, roughened by the insertion of muscles: its superior semicircular 

 ridge is extremely scabrous, and makes a well defined angle with the top of 

 the head. There is no hemispherical protuberance on each side of it, as in the 

 Asiatic Elephant, (see Plate tV., fig. 2, e;) on the contrary, the plane of the 

 occipital bone is slightly depressed near the centre of each side. The insertion 

 of the ligamentum nuchse is somewhat depressed and very scabrous, and makes 

 a triangular area, the base of which, being the line of the occipital ridge, is 

 five inches wide; from this it extends downwards eight and a half inches to- 

 wards the foramen magnum; it is divided symmetrically by a well-marked 

 vertical ridge. 



The occipital condyles rise immediately from the surface of the bone, instead 

 of standing out on a high base, as in the Elephant; they form one-third of a 

 circle, and measure nearly six and three-fourths inches in length, by two and 

 three-fourths in breadth. The plane of the occiput and the cuneiform process 

 form, in their relation to each other, a right angle, upon which is placed the 

 condyles. 



The cranium (see Plate II., fig. 1,) presents, in front, a flattened, or slightly 

 raised convexity, from the occipital ridge to the anterior nares, and exhibits 

 there an area of one foot eight inches long, by one foot two and a half inches 

 wide, between the temporal fossse. 



The plane of the occiput and the upper front part of the cranium make, at 

 their line of junction, a well defined angle of ninety -five degrees, (see Plate III.) 

 In an Elephant belonging to the Wistar Museum, the corresponding portion is 

 rounded, but if designated by supposititious planes, the latter would meet at 

 an angle of eighty-five degrees. 



The incisive fossa (see Plate IV., fig. 1, a,) of upper maxilla is distinguished 



