26 Transactions Texas Academy of Science. — 1906. 
the anterior border separate and tendinous, to be inserted immedi- 
ately anterior to the M. latissimus dorsi anterior. The two muscles 
are connected by a heavy fascia which extends from the posterior 
border of the anterior bundle to the mid point of the posterior one, 
and continues to their insertion. Origin in Aeronautes (Lat. d. p., 
PI. VI., figs. 52, 54) is tendinous from part of the fourth and the 
following dorsal vertebrae, and the anterior border of the ilium. It 
is inserted immediately anterior to one of the short heads, and be- 
tween it and the other, which comes from the foramen triosseum. 
The line of separation is not distinct between the two muscle bun- 
dles, and they become clearly separate only near their insertions. 
4. M. rhomboideus superficialis. In Geococcyx (Rh. s., PI. II., 
figs. 15, 19) it consists of two portions connected by fascia. Its 
origin is semitendinous from the two last cervical vertebrae, and 
the following dorsal ones. It is inserted fleshily on the anterior four- 
fifths of the dorso-median border of the scapula. Origin in Bubo 
(Rh. s., PI. IIP, fig. 26; PL IV., fig. 33) is tendinous from the second 
and following dorsal vertebrae, and from the anterior edge of the 
ilium. It is inserted fleshily on the entire dorso-median border of 
the scapula. Origin in Aeronautes (Rh. s., PI. VI., figs. 52, 56) is 
fleshy from part of the last cervical and following four dorsal verte- 
brae. It is inserted fleshily on the anterior half of the dorso-median 
border of the scapula. 
5. M. rhomboideus profundus. Origin in Geococcyx (Rh. p., 
PI. II., fig. 19) is semitendinous from the last cervical vertebra, the 
first, second, third and part of the fourth dorsal vertebrae. It 
inserts fleshily on the posterior dorso-median half of the scapula. 
Origin in Bubo (Rh. p., PI. III., fig. 26; PI. IV., fig. 33) is fleshy 
from second, third, fourth, fifth, and part of the sixth dorsal ver- 
tebrae. It inserts fleshily on the dorso-median border of the poster- 
ior two-thirds of the scapula. Origin in Aeronautes (Rli. p., PI. 
VI., fig. 56) is tendinous from the dorsal vertebrae following the 
fourth. It inserts fleshily on the posterior one-third of the dorso- 
median border of the scapula. 
6. M. scapuli-humeralis anterior. Origin in Geococcyx (Sc.-hu. 
a., PI. II., figs. 18, 19, 20) is fleshy on the dorsal surface of scapula 
between the M. rhomboideus superficialis and the M. subscapularis, 
beginning at the anterior edge of the M. scapuli-humeralis posterior 
and extending to the M. pars scapuli-cubitalis. It inserts fleshily 
between the short heads of the M. pars humero-cubitalis anterior to 
the insertion of the M. latissimus dorsi posterior, and reaching the 
foramen pneumaticum. In Bubo this muscle is absent. Origin in 
Aeronautes (Sc.-hu. a., PI. VI., figs. 51, 54, 56) is fleshy on dorso- 
