MUSCLES OF THE FORE LIMB 85 



Triceps. — This muscle springs from the greater part of 

 the humerus fleshily by two heads, of which one— that from 

 the tuberculum minus — is often tendinous. The name 

 triceps, be it observed, has been given to the muscle on the 

 understanding that the last-described muscle is a part of it. 

 Their tendons of insertion join. 



Expansor Secundwriorum} — This extraordinary muscle 

 appears to be partly a skin and partly a skeletal muscle. 

 A bundle of non-striated fibres arises near the secondary 

 feathers of the arm and ends in a tendon. This is occa- 

 sionally reinforced by a band of striated fibres arising 

 from beginning of ulna. The long tendon is inserted in 

 various ways. The typical condition (termed by GtAreod 

 ' ciconiine ') is for it to be inserted into the middle of a liga- 

 ment running from the scapulo-coracoid to the sterno- 

 coracoid articulation. Other modifications occur among the 

 gallinaceous birds {q.v.), &c. The muscle is totally absent 

 in Struthiones, Sphenisci, Alcae, Psittaci, the majority of Pico- 

 Passeres, and in a few species of groups where it is usually 

 present. 



Sterno-coracoideus. — This muscle, wanting only in the 

 Macroeliires, runs from the, anterior lateral border of the 

 sternum to the adjoining region of the coracoid. The muscle 

 shows every stage between a single muscle and a completely 

 double one,. It is double, for example, in Casuarius. In 

 Struthio, Chauna, and some other birds where there is but 

 one sterno-coracoid, it is the homologue (according to FxJE- 

 BRINGBR) of the deeper section of the double muscle. 



Scapulorhumeralis Anterior. — Euns from the beginning 

 of the post-glenoidal region of the scapula to the beginning 

 of the dorsal surface of the humerus. It is a muscle which is 

 frequently absent. Fuebeingbr failed to find it in Struthiones, 

 Sphenisci, Fregata, Chauna, Columbse, Pterodes, Chungdy 

 Bucorvus, &c. . . 



Scapulo-humeralis Posterior. — Contrary to the last this 

 is a large muscle and is never absent. It arises from the 



'Gakbod,' 'On the Anatomy of Chauna derbiana,' Ac, P. Z. S. 1876 

 p. 193, &c. 



