30 
Transactions Texas Academy of Science. — 1906. 
a. M. propatagialis longus (P. pat. 1., PI. II., figs. 14, 15) runs 
along in the anterior margin of the patagium and fuses with the 
inner surface of the skin covering the os magnum. In Bubo (P. pat. 
l. , PI. IV., figs. 33, 37) the two muscles are quite separated at the 
origin. The fibres of the longus are proximally not distinguishable 
from those of the m. pars thoracica. The fleshy portion become ten- 
dinous at the crista lateralis of the humerus and is fused with the 
skin covering the distal end of the radius. In Aeronautes (P. pat. 1., 
PI. VI., figs. 50, 52, 57) the two muscles are entirety separated. The 
longus consists of two distinct portions, • one coming from the sec- 
ond dorsal fifth of the clavicle, the ventral and large one from the 
middle third of the clavicle. The two fuse in the distal third of 
their fleshy bundles and continue in a common tendon to the os 
magnum, where it becomes split, one division being inserted on the 
ventral proximal border of the pollex digit, and the other near the 
mid point of the pollex digit on the dorsal surface. 
b. M. propatagialis brevis. In Geococcyx (P. pat. b., PI. IT., 
figs. 14, 15, 17) the main part of the tendon is inserted on the m. 
extensor metacarpi ulnaris (radialis?), one-fourth the length of the 
fleshy portion of the muscle from its origin. Prom this point a 
branch is sent to the patagium and there fades out in a fan-like ex- 
pansion. The other passes over into the heavy fascia extending from 
the anterior border of the radius down to the feathers. In Bubo 
(P. pat. b., PI. IV., figs. 33, 37) the brevis comes semitendinously 
from the dorso-median surface of the clavicle and from the anterior 
end of the scapula. At its lower corner it is fused to the m. del- 
toideus major. Prom its chest-facing surface comes off a strong- 
fascia which passes over the crista lateralis of the humerus and fades 
out into the m. pars thoracica at the base of the longus. From its 
distal end come off two strong tendons. The anterior one bifurcates 
half way to the fore arm. The anterior fork fuses with the tendon 
of the m. extensor metacarpi culnaris (radialis?), the other one 
crosses this muscle and continues distally, losing itself in the heavy 
fascia extending from the anterior border of the radius down to 
the feathers. The posterior tendon goes direct to the m. extensor 
metacarpi uluaris (radialis?), proximal to the fork of the anterior 
tendon, and fuses with it. At the point where the brevis becomes 
tendinous there is a short tendinous band coming off from its under 
surface and inserting on the crista lateralis of the humerus. In 
Aer'onautes (P. pat. b., PI. VI., figs. 52, 57) the brevis comes off 
from the dorsal end of the coracoid. It continues fleshily to the 
m. extensor metacarpi ulnaris (radialis?), and except at its lower 
edge, fuses with this muscle. Prom this edge comes off a short 
