520 THE VERTEBRATE SKELETON. 



the development of trochanters is slight, and the fibula though 

 slender is complete and articulates with the calcaneum. 



A third trochanter is found in the Tillodontia. 



In RODENTIA the femur is variable, the great trochanter is 

 generally large and so sometimes is the third as in the Hares. 

 In most Rodents as in the Beaver the fibula is distinct, some- 

 times as in the Hares it is united distally with the tibia. The 

 patella is well developed, and so too are the fabellae as a 

 general rule. 



GARNI VORA. In the Garni vora vera the femur (fig. 79, A) 

 is generally rather straight and slender, and has a very distinct 

 head. The fibula (fig. 79, C) is always distinct and there is 

 generally a considerable interval between it and the tibia. 

 Fabellae (fig. 79, 7) are commonly present. 



In the Pinnipedia the femur is short, broad and flattened, 

 having a prominent great trochanter. The fibula is nearly as 

 large as the tibia, and the two bones are generally ankylosed 

 together at their proximal ends. 



The Creodonta differ from all living Carnivores in having 

 a femur with a third trochanter. 



In the INSECTIVORA a third trochanter is sometimes 

 developed. The fibula is sometimes distinct, sometimes fused 

 distally with the tibia, thus differing from that of a Carnivore. 



In CHIROPTERA the femur is straight, slender and rather 

 short, with a small but well-developed head. The fibula may 

 be well developed or quite vestigial or absent. Owing to the 

 connection of the hind limb with the wing membrane the knee 

 joint is directed backwards. 



In PRIMATES the femur is rather long and slender, having 

 a nearly spherical head and large great trochanter. The tibia 

 and fibula are always distinct and well developed. Fabellae 

 are not found in the highest forms but are generally present 

 in the others. 



