34 ANATOMY OF A CHELONIAN. 



in form, though smaller. Each reaches for- 

 ward so as to meet a process sent back from the 

 pubic bone on the same side, and enclose a 

 large obturator foraynen. < 



72. The Hind Limb, larger and somewhat stouter than 

 the anterior, resembles it closely in general form and 

 in its position with reference to the axial skeleton (64). 



73. The femur is larger than the humerus, but re- 

 markably like it in shape. 



74. In the crus the tibia and fibula are distinct, and 

 each enters into the knee- and ankle-joints. The tibia 

 is larger than the fibula, and placed on its ventral side. 



75. The tarsus has two bones in its proximal row. 

 The larger of these {astragalus)^ placed on the tibial side, 

 is made up of a coalesced tibiale and intermedium. The 

 other bone in this row is the os fibulare (calcaneunt). 

 The distal row of the tarsus presents five bones {tarsa- 

 lia), of which that on the fibular side is much larger 

 than the others, and is regarded by some morphologists 

 as a metatarsal bone. If this be so, the proper tarsalia 

 are four in number : one each for the first, second, and 

 third digits, corresponding to the internal, middle, and 

 external cuneiform bones of human osteology; while 

 for the fourth and fifth digits there will be a single 

 tarsal bone, corresponding to the cuboid. 



76. Each digit of the foot has a metatarsal bone ; but, 

 accepting the above view as to the homology of the fifth 

 bone in the distal row of the tarsus, the fifth metatarsal 

 is very different in form from the rest. The great toe 



