C. J. Sundevall on the Wings of Birds. 437 



extending to the latter in the extensor and flexor carpi ulnares. 

 Thus the sinews are shorty and the arm itself acquires a uni- 

 formly thick and less elegant shape. (In those which have 

 a very long cubitus, Grus, Strix, Sic, the muscles are, how- 

 ever, only fleshy for | or f of their length.) Bony sinews 

 occur in sj^ecies of several Orders. 



b. The fascia ulnaris is thick, strongly sinewy, flat and of 

 uniform breadth, with definite edges which are not folded 

 down, lying upon the surface of the muscular layer, and occu- 

 pying the place of the sinus ulnaris. It starts from the ulna, 

 along the whole of the bone, by a strong lamella, which sepa- 

 rates ihe flexor carpi ulnaris from the flexor digitorum sublimis. 

 The latter consequently lies on the inner (radial) side, and 

 not in the middle upon the former ; it is always attached under 

 the fascia tendinea, and does not extend to the base of 

 the cubitus ; it is usually fleshy nearly to the ligamentum 

 carpi. 



c. The ulna, towards the upper extremity, is gradually 

 curved for a considerable distance (at least from ^ to §), but 

 straight in the anterior part (consequently somewhat bowed, 

 but not S-shaped) ; the condyle projects downwards a little 

 only in consequence of its thickness. By this means the 

 flexor carpi ulnaris comes to project only slightly behind the 

 ulna. 



d. The humerus is to a great extent uncovered, in conse- 

 quence of the shortness of the mu^c. deltoideus, which in most 

 forms reaches half the length of the humerus or is rather less, 

 and is very narrow. Only in Columba does it reach | ; in 

 the Water-birds [Anas, Sterna, Alca) it is quite small. 



With regard to the arrangement of the muscles the follow- 

 ing may be remarked in general : — 



The extensor carpi radialis longus is not larger, sometimes 

 narrower than any of the others — e.g. the flexor carpi ulnaris, 

 or the extensor carpi ulnaris, or the pronator, &c. 



The extensor carpi radialis brevis, on the contrary, is large 

 and strong (except in the Natatores). 



The extensor carpi ulnaris is usually fleshy to the carpus, 

 and terminates with its sinew on the underside of the middle 



SER. V. VOL. IV, 2 I 



