1905. J ANATOMY OF THE LEATHERY TURTLE. 301 



Origin : from the ventral surface of the outer third of the coracoicl. 

 Insertion : upon the humerus in the hollow between the lateral 

 and median processes, just proximal to the insei'tion of the 

 pectoralis. 



A thin sheet of muscle capping the shoulder. The median 

 nerve follows its hinder border, lying between it and the coraco- 

 brachialis brevis internus. 



Coraco-hrachicdis brevis internus (text-figs. 58, 60, 61, & 64. 

 46). — Origin : from the outer three -fourths of the hinder border of 

 the coracoid, encroaching somewhat upon both dorsal and ventral 

 surfaces. Insertion : upon the processus medialis of the humerus. 



An undetermined muscle (text-figs. 60 & 62. 46 «), pi-obably a 

 separate part of the coraco-brachialis brevis internus. Origin : 

 from the ventral and posterior border of the coracoid, extending 

 slightly on to the coraco-scapular ligament. Insertion : upon 

 the extensor surface of the median process of the humerus between 

 the insertions of the coraco-brachialis brevis internus and of the 

 subscapularis. 



Coraco-antehrachialis {biceps) (text-figs. 58, 61, & 64. 47). — 

 Origin : from the median end of the ventral surface of the 

 coi'acoid, posterior to the oiigin of the supra-coracoideus. In- 

 sertion : by a round tendon to the heads of the radius and ulna. 



This muscle passes into the arm between the head of the hu.merus 

 and the median process, overlying the median nerve. As it 

 enters the arm it forms a single rounded tendon that extends to 

 the hollow of the elbow. Here, the tendon unites to a gi'eat 

 extent with the dense connective tissue upon the surface of the 

 humero-radialis longus dorsalis, but strands can be ti'aced to both 

 the ulna and radius. Fiirbringer describes a separation of the 

 muscle into definite superficial and deep parts during its passage 

 along the humerus. 



Humero-antebrachialis inferior (text-fig. 64. 48). — Origin : 

 from the flexor surface of the humerus distal to the lateral 

 process. Insertion : by tendon upon the flexor surface of the 

 head of the ulna, in common with the tendon of the biceps. 



Testo-humeralis dor si (latissimus dor si) (text -figs. 55 & 62, 

 49). — Oiigin : fiom the carapace along the anterior border of the 

 second rib just in front of the testo-coracoideus, and along the 

 outer margin of the scapular fossette to the posterior limit of the 

 nuchal plate. Insertion : upon the middle of the extensor surface 

 of the humerus between the insertion of the subscapularis and 

 the origin of the anconfeus. 



Fiirbringer states that in Ghelone (adults) the origin of this 

 muscle extends back to the third rib, but that this is a backward 

 migration that takes place after embryonic lif^ 



Scapido-clavicido-plastro-hicmeralis (Deltoideus) (text-figs. 58, 

 59, & 62, 50). — This consists of two entirely independent 

 muscles : — 



a. Pars clavicido-plastro-himiercdis. — Origin : from a median 

 ventral raphe in front of the shoulder-girdle and from the anterior 



