THE FROG 37 



foot of the spotted salamander. But in most animals some of 

 the carpal and tarsal bones are fused together, as in the frog. 

 In man we find in the carpus that the radiale, intermedium, 

 and ulnare are present as separate bones, and they are called 

 scaphoid, lunar, and cuneiform, respectively. The centrale 

 is present in the foetus, but becomes fused with the third bone 

 of the distal row to form the os magnum. The first and 

 second bones of the distal row, called the trapezium and 

 trapezoid, are separate ; the fourth and fifth are fused together, 

 and are called the unciform. In the foot the tibiale and 

 intermedium are fused to form the astragalus, the fibulare 

 forms the calcaneum. The centrale remains separate, and is 

 called the navicular ; the first, second, and third distals are 

 called the ento-cuneiform, meso-cuneiform, and ecto-cuneiform, 

 respectively ; the fourth and fifth are fused together to form 

 the cuboid. After this explanation the limb bones of the frog 

 should present no difficulty. 



