408 



ANATOMY OF VERTEBRATES. 



54, is but half the length of the ulna: in all Bruta it is free, and 

 rotates on the ulna. The four carpal bones of the proximal row 

 are distinct from one another. 



276 



V \ 



Bones of fore-arm and foot, Dasypus gigas. cli. 



The scaphoid, ib. s, is the smallest of the four bones of the 

 proximal row. The pisiform, p, articulates to the cuneiform, c, 

 and ulna, and extends, palmad, to the lunare, with which it forms 

 a large articular cavity, upon which the palmar patella plays. In 

 some the trapezium, t, is distinct; in others it is connate with 

 the trapezoides. The magnum, m, in most coalesces with the 

 base of the cubical metacarpal of the digitus medius, ill. The 

 outer part of the base of that metacarpal rests upon the unci- 

 forme, u, which also supports the small but thick cubical meta- 

 carpus of the annularis, iv, and rudiment of the metacarpal 

 of the minimus, v. The medius and annularis have each but 

 two phalanges ; the long and slender index retains the normal 

 number of three phalanges ; the base of its metacarpal is wedged 

 between that of the third, the trapezoides, and the trapezium. The 

 chief peculiarity is the very large sesamoid bone developed in the 

 flexor tendons, and filling the palmar aspect of the fore-foot : a 

 second sesamoid is attached by ligament to the apex of the large 

 palmar one. An accessory ossicle, x, is wedged into the outer 

 side of the carpus in Das. gigas. In Das. Peha, fig. 260, there 

 are four digits on the fore-foot, the two middle much exceeding 

 in length and strength the outer and inner ones : the pollex, i, 

 is obsolete. The femur, figs. 260, 277, 65, presents a third tro- 

 chanter. The proximal and distal extremities of the tibia, 66, 

 and fibula, 67, are connate : their shafts subsequently coalesce 

 therewith, so that a single epiphysis answers to the shafts of both 

 bones at each of their extremities, in the immature Armadillos. 

 The naviculare is remarkable for its two inferior tuberosities, 

 the interspace between which receives the under part of the 

 entocuneiform bone. In Das. sex-cinctus it sends downward a 

 process, like that in some Rodents. The calcaneum is less pro- 



