SKELETON AND TEETH 



85 



movement. On the outer side of the upper end of the femur 

 is a large, roughened protuberance, which often rises higher 



ft.tn 



int.con 



Fig. 34. — Left femur of Wolf, front side. 

 A. , head, gt.tr., great trochanter, tr.2, 

 second trochanter, int. con., internal 

 condyle, r.g., rotular groove, exl. 

 con., external condyle. 



Fig. 35. — Left femur of Horse, tr .3, 

 third tiochanter. Other letters as in 

 Fig. 34, than which this drawing is 

 very much more reduced. 



than the head and is called the great trochanter; another, the 

 second or lesser trochanter, is a small, more or less conical prom- 

 inence on the inner side of the shaft, below the head. These 

 two processes are well-nigh universal among land mammals ; 

 and in a few of the orders occurs the third trochanter, which 

 arises from the outer side of the shaft, usually at or above the 

 middle of its length. Though comparatively rare in the 

 modern world, the third trochanter is an important feature, 

 and the early members of most, if not all, of the mammaUan 

 orders possessed it. The shaft of the femur is elongate and, 

 except in certain very bulky mammals, of nearly cylindrical 

 shape. The lower end of the bone is thick and heavy and bears 



