COMPARATIVE MEASUREMENTS. 



109 



Its superior articulating surface is divided into two parts by the spine, 

 both of which are a little excavated ; the internal has nearly a circular form, 

 and the external rather an oval. They measure as follows : — 



MASTODON. ELEPHANT. 



The internal in diameter 



The external transversely 



The external antero-posteriorly . . . . . 



Transverse diameter of the lower articulating surface 

 Anteroposterior diameter of the lower articulating surface 



Inches. 



4 

 3| 



4| 



3| 



Inches. 



4 

 3| 



5h 



This surface is excavated for the reception of the astragalus, and sur- 

 mounted by a large peripheral ridge, most prominent at the malleolus 

 internus. It is interrupted externally by the inferior head of the fibula. 

 The tuberosity of the tibia is less prominent than in the other specimens. 



In comparing the articular surfaces of the Baltimore tibia, we find that 

 they differ considerably. Instead of being divided into two nearly equal 

 surfaces by the spine, the internal, in this specimen, has double the 

 dimensions of the external ; the internal condyle of the femur, as before 

 mentioned, projects inward to occupy this surface. The articulating surface 

 for the external condyle has not more than half the superficies of the 

 internal; it is also very oblique, forming nearly an angle of 45° at its 

 internal edge. 



FIBULA. 



It is situated exteriorly to the tibia, except at the superior extremity, 

 which is a little behind. 



It measures in length 

 Circumference above 

 Circumference below 

 Circumference, middle 



18 



10| 



14 



3! 



