MUSCLES OF THE FORE LIMP, 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 Secundarionun. 1 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 GAEEOD 

 ' 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, Alcse, Psittaci, the majority of Pico- 

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

 present. 



Sterno-coracoideiis. This muscle, wanting only in the 

 Macrochires, 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 FUR- 

 BEINGER) of the deeper section of the double muscle. 



Scapulo-humeralis Anterior.- Buns 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. FURBRINGER failed to find it in Struthiones, 

 Sphenisci, Fregata, Chauna, Columbae, Pterodes, Chwnga, 

 Bucorvus, &c. 



Scapulo-humeralis Posterior. Contrary to the last this 

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



1 GAREOD, 'On the Anatomy of Chauna di'i-Liana,' &c., P. Z. S. 1876 

 p. 193, &c. 



