SKELETON OF LOWER LIMB. 



I/. The BONES OF THE PROXIMAL PART OF THE TARSUS 



are always the largest and most important. 



The astragalus and os cakis, and probably also the 

 ncruicularg) may be represented by a single bone, as in 

 many Lizards, and they may intimately fuse at an early age 

 with the distal end of the tibia, as in almost all Birds. 



In this latter case these bones unite very early into one, 

 which remains long distinct from the tibia, only in the 

 Ostrich, Rhea, and Emeu ; and for some time after hatching 

 jn the Dorking Fowl. 



FIG. 176. RIGHT FOOT OF EMEU. 



, astragalus; d 2 d* y second, third, 

 and fourth digits : m, metatarsals 

 anchylosed together except at their 

 distal ends ; t, tibia ; 1 2 , distal tarsal 

 element. 



FIG. 177. LEFT FOOT OF A MONITOR 

 LIZARD (Varamis}. 



f, fibula ; tn T in 5, the five metatarsals, 

 in T being that of the hallux ; /, tibia ; 

 i, astragalo-calcaneum ; 2, cuboides; 

 3, ecto-cuneiforme. 



In Lizards this compound bone is extended transversely, 

 but very little backwards. It articulates with both the tibia 

 and fibula above, and has an irregular surface below for the 

 reception of the more distal tarsal bones. 



