Vol. XIV, 



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] Lkach, The Myology of the Bell-Magpie. 17 



74. The extensor digitorum communis. 



75. The supinator brevis. 



76. The flexor metacarpi radialis. 



77. The pronator brevis. 



78. The pronator longus. 



79. The extensor ossis metacarpi pollicis. 



80. The anconeus. 



81. The extensor indicis longus. 



81 a. The flexor digitorum sublimis. 



82. The flexor digitorum profundus. 



83. The flexor carpi ulnaris. 



84. The flexor carpi ulnaris brevior. 



73. The extensor metacarpi radialis longior, or longus [22] [24], 

 agrees with Shufeldt's description of this muscle in the American 

 Raven. It arises from the humerus, and is inserted by a very 

 strong tendon into the apex of the metacarpus. It receives the 

 tendon of the tensor patagii brevis (68), as already described. 



74. The extensor digitorum communis [24] arises from the 

 humerus just below the external condyle. It forms a long spindle- 

 shaped muscle below the extensor metacarpi radialis longior (73), 

 and soon forms a long tendon, which passes in a groove over the 

 distal end of the ulna. It gives off a small branch to the outer 

 side of the base of the pollex. It is continued down a groove on 

 the metacarpus through a pulley provided for it, and is inserted 

 near the front edge of the proximal phalanx of the index finger. 



75. The supinator brevis lies under the extensor digitorum 

 communis (74). It arises from the external condyle of the humerus 

 below the tendon of (74), and passes directly across to be attached 

 to the outer side of the radius for about one-third of its length. 

 It is a feeble muscle in the birds dissected. 



76. The flexor metacarpi radialis [24] is the large lower muscle 

 of the forearm. It arises by two heads — one, tendinous, from 

 the external condyle of the humerus, and the second, also ten- 

 dinous, from the ulna beyond the olecranon process. It is closely 

 attached to the bone for a considerable distance. Becoming 

 tendinous, it passes through the fibrous sheath on the outer side 

 of the distal end of the ulna, and goes directly to be inserted on 

 a prominent process on the upper hinder border of the metacarpal. 



yj. The pronator brevis arises tendinous just above the internal 

 condyle of the humerus and passes across to be inserted on the 

 ulnar side of the radius. 



78. The pronator longus is a more powerful muscle, similar to 

 77. It arises below the latter from the internal condyle of the 

 humerus, and passes across, under, and behind yy to be inserted 

 below it on the radius. 



79. The extensor ossis metacarpi pollicis [24] is an extremely 

 fine thin muscle with a hair-like, ghstening tendon. It arises in 

 front of the greater sigmoid cavity of the ulna, and forms a straight, 



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