C. J. Sundevall on the Wings of Bii'cls. 431 



sinew. It seems reduced merely to act upon tlie capsule oi 

 the joint; supination is impossible. Its development seems to 

 -proceed pari passu with that of the pronatoi' superior (No. 13) ; 

 they generally terminate close together upon the radius. 



B. On the inner (flexor) side of the cubitus, springing from 

 the humeri condylus internus and the ulna. These are 

 flexors in their nature. 



The muscles of the forearm seen from this side form 

 three great masses or gi'oups, the sinews of which are 

 separated by the above-mentioned pits when the latter are 

 present. The anterior mass consists of the preceding Nos. 1 

 and 7, the posterior of Nos. 8-10, and 15, the middle one at 

 the upper part of the pronaiores, and then of Nos. 11 and 1.2. 



a. Long muscles for the hand. 



8. Flexor carpi ulnaris, from the condylus internus to the 

 OS pisiforme, below the fascia ulnaris or behind (beyond) it; 

 first beside the ulna, then behind it, as if outside the arm. 

 It is usually one of the largest cubital muscles, very fleshy 

 with a strong sinew, the principal flexor muscle of the hand. 



9. Rector remigum cubiti, constitutes as it were a part of 

 the preceding, forming its hinder edge from the condylus 

 internus ; it gives oft' small sinews to all the remiges, and 

 finally one to the ligamentum carpi. It therefore corresponds 

 to the palmaris longus in man. 



10. Flexor digiti sublimis, a long, slender, generally 

 very small muscle, attached beneath the fascia ulnaris and 

 quite concealed by it. It lies either on the sui-face of No. 8, 

 or close to it on the radial side. The sinew is usually fine, 

 passes round the radial side of the os pisiforme, obliquely 

 over the metacarpus to the radial side of its apex, and 

 attaches itself at the base of the first phalange, quite at the 

 radial margin of its articulating surface ; it seems therefore 

 to act only as an extensor. (The sinew may be traced to 

 the base of the second phalange in Strix nisoria, Anas 

 glacialis, and, according to Schopss, in Psittacus, Fulica, 

 and Aptenodytes, but not in Falco paluinbarius, &c.) 



