236 THE VERTEBRATE SKELETON. 



terminations which closely approach one another, while else- 

 where the bones diverge considerably. 



The terminations of all three of the leg bones are formed 

 by epiphyses. 



The Pes consists of the tarsus or ankle, and the foot, 

 which is made up of five digits. 



The tarsus. The tarsal bones of the Turtle do not retain 

 their primitive arrangement to such an extent as do the 

 carpals. They are arranged in a proximal row of two and a 

 distal row of four. Of the bones in the proximal row the 

 postaxial one is much the smaller and is the fibulare ; the 

 larger pre-axial one (fig. 40, B, 15) represents the tibiale, 

 intermedium, and centrale fused, and articulates with both 

 tibia and fibula. The first three distal tarsalia are all small 

 bones and are very similar in size, and each articulates regu- 

 larly with the corresponding metatarsal. The fourth bone 

 (fig. 40, B, 19) is much larger, and represents tarsalia 4 and 5 

 fused. The first two distal tarsalia articulate with the pre- 

 axial tarsal of the proximal row, the third only with its neigh- 

 bours the second, and the fused fourth and fifth. The latter 

 articulates with both bones of the proximal row. 



Each digit consists of a metatarsal and of a varying num- 

 ber of phalanges. 



The metatarsals. The first metatarsal (fig. 40, B, 20) 

 is broad and flattened, the second, third and fourth, are all 

 elongated bones with nearly flat terminations formed by small 

 epiphyses/ The fifth is large and flattened, and the articular 

 surface for the phalanx is situated somewhat laterally. 



The phalanges. The first digit has two phalanges and is 

 the stoutest of them all ; its distal phalanx is sheathed in a 

 large horny claw. The other digits, of which the third is the 

 longest, have each three phalanges. The distal phalanges of 

 the second and third digits are flattened and pointed and bear 

 small horny claws. 



