Studies on Avian Anatomy. — II. 
31 
tendon, which merges into the upper distal corner of the m. del- 
toideus major. 
2. M. metapatagialis. In Geococcyx (Met., PL II., fig. 15) it con- 
sists of two narrow bands. The dorsal one comes from the facing 
ends of the spines of the two dorsal vertebrae preceding the last. It 
is inserted on the skin above the m. pars humero-cubitalis somewhat 
proximal to the mid point of the humerus, the insertion is at the 
base of the humeral feather tracts.' The ventral one comes from the 
anterior border of the first sternal rib near its articulation with the 
ventral segment. It meets and fuses with the dorsal band at its in- 
sertion. In Bubo (Met, PI. III., fig. 25;' PI. IV., fig. 33) the nar- 
row dorsal band arises from the anterior dorsal border of the ilium, 
and inserts on the skin a little proximal to the mid point of the 
humerus. The ventral portion is much broader. It has its origin 
in two scallops on the fourth and fifth sternal ribs, and fuses with 
the insertion of the dorsal branch. In Aeronautes (Met., PI. VI., 
fig. 51) only the ventral band was present. It comes from the 
third and fourth sternal ribs at the base of their processus uncinatL 
3. M. biceps brachii. In Geococcyx (Bi., PI. II., figs. 14, 16) 
it has a tendinous origin on the antero-lateral surface of the cora- 
coid, and on the tuberculum mediate of the humerus. It inserts by 
two short tendons on facing surfaces of ulna and radius just be- 
yond the proximal border. In Bubo (Bi., PI. IV., figs. 30, 37) the 
origin is tendinous on the anterior lateral surface of the coracoid 
and on the tuberculum mediale of the humerus. It inserts by two 
tendons on facing surfaces of ulna and radius beyond the proximal 
border. In Aeronautes (Bi., PI. VI., fig. 53) it arises by one long 
tendon from the lateral border of the anterior end of the coracoid. 
It inserts by one delicate tendon on the ulna facing surface of the 
radius. 
Pars propatagialis m. bicipitis was absent in all the birds. 
4. Triceps cubiti. In all the birds this consists of two separate 
parts, one m. pars scapuli-cubitalis, and two m. humero-cubitales. 
a. Pars scapuli-cubitalis. Origin in Geococcyx (Pars. sc. cub., 
PI. II., figs. 15, 19, 20) is semitendinous on the neck of the scapula, 
and the outer surface of the glenoid fossa. It inserts on the ulna 
between the olecranon process and the external condyle. In Bubo 
(Pars. sc. cub., PL III., figs. 26, 28) the origin is semitendinous on 
the neck of the scapula. As the muscle passes over the m. latis- 
simus dorsi anterior it gives off a strong flat tendon which passes 
to the humerus anterior to the m. latissimus dorsi anterior, and 
fuses with the small tendon of the m. latissimus dorsi posterior. It 
inserts by a broad tendon beyond the proximal rim of the external 
