43 i C. J. Snndevall on the Wings of Birds. 
The cubitus has no more than these 16 muscles. Of those 
which occur in man there are wanting therefore :—Among the 
extensors, three belonging to the thumb and one to the little 
finger; among the flexors, one to the thumb and the pronator 
quadratus; or all the proper long muscles of the thumb, and 
one which could not act. Other peculiarities of the class 
are :—The double pronator and the single supinator, the 
course of the sinews from the flexores digitorum, ft. carpi 
radialis, and extensor digitorum, the size of the extensor carpi 
radialis longus and anconceus parvus (?No. 6), and lastly the 
addition in some forms of No. 15 ( humero-ulnaris internus ). 
One could scarcely suppose that there would be so little 
difference between the muscles of the bird’s wing and the 
human arm ! 
C. Muscles of the humerus, which still more resemble 
those of man. They are :— 
17. Extensor antibrachii (or triceps'), almost exactly as in 
man, but wanting the caput internum. 
18. Flexor antibrachii (or biceps ) as in man. 
The Anconceus parvus has already been mentioned, No. 6; 
as also the Brachialis internus, No. 16. 
Of the muscles of the shoulder we shall in what follows 
mention only the deltoideus, in order to avoid going into too 
many specialities here; but we will nevertheless remark that 
equally distinct differences, as in the forearm, present them¬ 
selves, between different groups of birds, in the other muscles 
of the shoulder and those of the trunk. 
In order to make a comparison between the muscles of 
the arm in the orders of birds, I have myself investigated them 
in 27 species selected from all orders, and can, moreover, 
avail myself of Schopss’s excellent descriptions of 11 (four of 
w T hich, however, are the same) ; namely:— 
Oscines : Corvus cor one, Schopss ; Garrulus glandarius, 
Sch. etipse; Pyrrhula vulgaris, Emberiza citrinella, Parus 
cristatus, and Hirundo rustica. 
Coccyges (sensu latiori) : Cypselus apus, Picus major, 
