i9°5-] 



ANATOMY OF PHALiENOPTILUS, R1DGWAY. 



humerus, and is almost concealed at its origin by the strong tendons 

 of the flexor digitorum sublimis. It is split in two by the extensor 

 indicis longus. The fibers of the upper half pass obliquely over 

 to the radius and are inserted on that bone under the pronator 

 sublimis, extending about as far distal) y as that muscle. The 

 lower half bends under the m. extensor indicis longus and is inserted 

 on the radius in a position corresponding to the upper half. This 

 muscle is not shown in the drawings. 



b. M. entepicondylo-ulnaris is absent in this bird. 



7. M. ectepicondylo-ulnaris (Ect. u., PI. V, Fig. 19) arises by 

 a strong tendon from the posterior projection of the external con- 

 dyle of the humerus below the m. extensor digitorum communis, and 

 is covered by the tendon of the m. extensor carpi-ulnaris (radialis ?). 

 It passes over to the anterior surface of the ulna, and is there 

 inserted fleshily for fully two thirds the length of that bone. 



8. M. ectepicondylo-radialis (Ect. r., PI. V, Fig. 19). This 

 muscle arises from the posterior projection of the external condyle 

 of the humerus, below the origin of the m. extensor digitorum com- 

 munis and below the insertion of the second forward directed 

 branch of the m. propatagialis brevis. It passes directly over to the 

 proximal end of the radius and is inserted fleshily along its dorsal 

 surface for about one third its length. 



9. M. flexor carpi ulnaris (E. carp, ul., PI. V, Fig. 24). This 

 is the largest muscle of the forearm. It arises by a strong, flat ten- 

 don from the posterior border of the external condyle of the hume- 

 rus. It is held in place by a ligament which passes from the con- 

 dyle over and under the tendon to the base of the olecranon process 

 of the ulna, thus forming a loop. The muscle runs along the ven- 

 tral surface of the ulna and at about the middle of that bone 

 separates into two tendons. Both continue distally to become 

 inserted on the outer border of the os ulnare, the more delicate on 

 the lower edge. 



10. M. ulni metacarpalis veiitralis ([//. met. v., PL V, Fig. 24). 

 This muscle arises fleshily from about the middle three fifths of the 

 ventral and posterior surface of the ulna, and is broadest at the 

 distal end immediately before passing over into the tendon which 

 crosses in front of the os radiale, to the surface of the third meta- 

 carpal and is inserted on its dorsal proximal projection. It is cov- 

 ered by the tendons of other muscles which find their insertion in 



