1. humerus. 2. radius. 3. ulna. 4. radiale. 5. ulnare. 6. pisiform. 7. patch of cartilage representing carpalia 1 and 2; between it and the radiale should be another flattened patch, the centrale. 8. carpalia 3, 4, and 5 (fused). 9. first metacarpal. 10. proximal phalanx of second digit. 11. second phalanx of fifth digit. 12. femur. 13. tibia. 14. fibula. 15. tibiale, intermedium and centrale (fused). 16. fibulare. 17. tarsalia 1, 2, and 3 (fused). 18. tarsalia 4 and 5 (fused). 19. first metatarsal. 20. ungual phalanx of second digit. 21. fifth metatarsal. The =radius= and =ulna= are nearly equal in size and each consists of a long shaft terminated at either end by an epiphysis. The =radius= (fig. 48, A, 2) or pre-axial bone is slightly the smaller of the two. It has a straight cylindrical shaft and is slightly and nearly evenly expanded at either end. The proximal end which articulates with the humerus is flat or slightly concave, the distal end which articulates with the carpus is slightly convex. The =ulna= (fig. 48, A, 3) or postaxial bone is a curved bone rather larger than the radius. Its proximal end is large and convex, but is not drawn out into an olecranon process. The =Manus= consists of the =carpus= or =wrist=, and the =hand=. The =Carpus=. This differs considerably from the more primitive type met with in the Turtle. It consists of six elements arranged in a proximal row of three and a distal row of two, with one intervening. The bones of the proximal row are the radiale, the ulnare, and the pisiform. The =radiale= (fig. 48, A, 4) is the largest bone of the carpus: it is a somewhat hour-glass shaped bone, with its ends formed by flattened epiphyses. It articulates by its proximal end with the whole of the radius, and partly also with the ulna, and by its distal end with the centrale. The =ulnare= (fig. 48, A, 5) is a smaller bone, also somewhat hour-glass shaped; it articulates proximally with the pisiform and radiale, not quite reaching the ulna. The third bone of the proximal row is the =pisiform= (fig. 48, A, 6), an irregular bone, articulating with the ulna, radiale, and fifth metacarpal. The =centrale= is a flattened cartilaginous element applied to the distal surface of the radiale. The distal row of carpals consists of two small structures. The first of these forms a small cartilaginous patch, which is wedged in between the first and second metacarpals, the centrale and the bone representing carpalia 3, 4 and 5; this cartilaginous patch represents =carpalia 1 and 2= (fig. 48, A, 7). The bone representing =carpalia 3, 4 and 5= is a good deal larger, rounded, and well-ossified; it articulates with the ulnare, the pisiform, and the third, fourth, and fifth metacarpals.