106 The Alligator and Its Allies 
Triceps internus, Theil der Portion humérale 
interne du triceps brachial, [Mittler] vom Humerus 
ausgehender Kopf des Streckmuskels des Vor- 
derarmes). Springs from the middle of the ex- 
tensor surface of the humerus between the lateral 
and medial heads. 
(e) Caput Humerale Mediale (Longius caput m. 
brachiei interni, Theil des [inneren] kurzen Kopfes 
- des dreiképfigen Streckers, Theil der Portion 
humérale interne du triceps brachial, [Innerer] vom 
Humerus ausgehender Kopf des Streckmuskels 
des Vorderarmes, Theil des Triceps Nr. 3, Theil 
des Triceps internus). This head originates on 
the medial part of the extensor surface of the 
upper arm at the end of the medial process where 
it is united with the scapulo-humeralis profundus 
muscle. 
The muscle mass formed by the union of all the 
above heads goes over, as a broad and somewhat 
thick tendon, to become inserted on the proximal 
part of the ulna. 
Humero-radialis (Plate I., Figs. 1 and 4, hr) 
(Caput longum m. bicipitis, Eigener kurzer Beuger, 
[Zweiter] vom Oberarm: ausgehender Beuger, 
Brachialis externus, Portion a of Brachizus). 
A fairly large muscle on the outer side of the upper 
arm, lying between the brachialis inferior and 
caput humerale laterale muscles, with both of 
which it is, at the beginning, united. It originates 
with its deeper and chief mass from the outer 
