28 
Transactions Texas Academy of Science. — 1906. 
m. subscapularis interims. Origin in Aeronautes (Ser. s. a., Pi. 
VI., fig. 51) is fleshy on the anterior border of the free rib and its 
processus uncinatus and from the corresponding portion of the first 
sternal rib. It inserts tendinously on the ventral border of the scapula 
dividing the m. subscapularis into a large m. subscapularis externus 
and a small m. subscapularis interims. 
10. M. serratus superficialis posterior. Origin in Geococcyx (Ser. 
s. p., PI. II., fig. 18) is fleshy, in three scallops, the posterior border 
of the second free rib, first and second sternal ribs, and their pro- 
cessus uncinati. The insertion on the ventro-median border of the 
scapula is tendinous except at the tip of that bone. This tendinous 
sheet is continuous with the posterior border of the anterior part 
of this muscle. Origin in Bubo (Ser. s. p., PI. III., fig. 25) is 
fleshy in four teeth from the second, third and fourth sternal ribs 
and their processus uncinati. The insertion on the ventro-median 
border of the scapula is tendinous except at the tip of that bone, 
where it becomes fleshy. This tendinous sheet is continuous with 
the posterior border of the anterior muscle bundle. Origin in Aero- 
nautes (Ser. s. p., PL VI., fig. 51) is fleshy in four teeth from the 
second, third and fourth ribs and their processes uncinati. It in- 
serts fleshily on the ventro-median border of the last fifth of the 
scapula. 
11. M. serratus profundus. In Geococcyx (Ser. p., PI. II., fig. 
18) it consists of three portions. The first bundle arises from the 
transverse process of that cervical vertebra preceding the last, and 
aponeurotically from the muscles of that region, the second from 
the process of the last cervical vertebra, the third partly from the 
process of the last cervical vertebra, but mainly from the first short 
rib, the upper half. They insert on the posterior two-thirds of the 
median surface of the scapula. In Bubo (Ser. p., PI. III., fig. 25) 
it consists of two bundles. The first comes from the transverse 
process of the first dorsal vertebra and the contiguous portion of the 
free rib; the second from the first sternal rib near its dorsal articu- 
lation, dorsal surfaces of third and fourth ribs, and from the inter- 
costal spaces. Both bundles insert on the posterior median surface 
of the scapula, less than half. In Aeronautes (Ser. p., PI. VI., fig. 
51) it consists of two bundles. The first portion coming from the 
posterior border of the free rib from its dorsal articulation, down 
almost to the processus uncinatus; the second from the posterior 
border of the first sternal rib and its process uncinatus. The two 
portions insert on the middle third of the median surface of the 
scapula. 
12. M. sterno-coracoideus. Origin in Geococcyx (St.-co., PI. II., 
