196 EL EMENTA RY ANA TOM K [LESS. 



animals, only the largest beasts forming an exception in this 

 respect. 



As the longest bone of the leg (i.e. in the proportion in which 

 it exceeds the length of the tibia) the femur of man is dis- 

 tinguished from that of all Birds, and from that of almost all 

 other Mammals except of those Cetaceans which have a rudi- 

 mentary femur and a still more rudimentary tibia. Yet oc- 

 casionally (as e.g. in the Great Ant-eater 

 and certain Apes) the femur notably 

 exceeds the tibia in length. 



In many Reptiles and Tailed-Batra- 

 chians, however, the femur exceeds the 

 tibia as much as or more than in man, 

 and that not only in forms like Boa, 

 where both bones are, though in differ- 

 Fir,. ^.-SKELETON OF ent degrees, rudimentary, but also where 

 RUDIMENTARY PELVIC both are fairly developed. 

 LIMB OF Liaiis. For all that the several parts of the 



(After Furbringer.^ femur may exhibit different degrees of 

 /, femur ; z'/, ilium ; pi, development in different animals, yet on 

 pubo r ischium ; t, tibia. the wn ple it is a substantially constant 

 bone as to its form and structure ; more 



so even than is the case with the humerus, as the femur 

 never attains the great relative length which the humerus 

 attains in the Bats, nor is it ever reduced to the shortness 

 and thickness which that part presents in the Mole. 



In the proportion which it bears to the hind limb as a 

 whole, the femur of man is exceptionally developed, though 

 not quite so much so as in many Reptiles and Tailed-Batra- 

 chians. Its proportion, however, may become almost insig- 

 nificant, even in Mammals, as in the Seals. It is in these 

 aquatic Carnivora, and in the extinct Ichthyosaurus, that the 

 -femur is relatively at its shortest. 



It is a short bone (when compared with the leg and foot) 

 in the Ruminants and Horse family. 



The curvature which the shaft presents in man may be 

 exaggerated, as in Tortoises, while the bone may almost 

 become straight, as in the Lemurs, Carnivora, Bats, &c. 



The development of its neck is a character which the 

 femur of man by no means shares with that of all Vertebrates ; 

 on the contrary, the neck of the bone is most exceptionally 

 developed in him. In the majority of cases (as e.g. in Birds) 

 there can hardly be said to be any neck, and in many forms, 

 e.g. the Rhinoceros, there is none whatever. 





