THE HIND-LIMB. 323 



8. The tarsus (fig. 61) consists, in the rabbit, of six bones, 

 arranged, like the bones of the wrist, in a proximal 

 and a distal row, with a central bone between them. 

 The typical tarsus exactly corresponds to the typical 

 carpus in number and arrangement of bones. 



a. The proximal row of tarsals consists of two bones. 



i. The astragalus, which probably corresponds to 

 the tibiale and intermedium of the typical 

 tarsus fused together, lies on the inner or 

 preaxial side of the tarsus : it articulates by a 

 prominent pulley-like surface with the distal 

 end of the tibia. 



ii. The calcaneum, or fibulare, is the largest bone 

 of the tarsus : it lies along the outer side of 

 the astragalus, articulating with the fibula, 

 and is produced backwards into the large 

 calcaneal process or heel. 



b. The central bone. 



i. The naviculare, or centrale, is placed immedi- 

 ately in front of the astragalus. It sends 

 forwards a large process along the ventral 

 surface of the foot. 



c. The distal row of tarsals consists of three bones, the 



innermost or preaxial bone of the typical tarsus 

 being absent, together with the digit which it 

 supports, though probably represented by the 

 process at the proximal end of the second meta- 

 tarsal ; while the two outer tarsalia, like the 

 corresponding carpalia, fuse together, 

 i. The second tarsale, or meso-cuneiform, is very 

 small : it articulates with the navicular, and 

 supports the second metatarsal, 

 ii. The third tarsale, or ecto-cuneiform, hes to the 

 outer side of the meso-cuneiform. It arti- 

 culates with the navicular, and supports the 

 third metatarsal. 



y2 



