112 The Alligator and Its Allies 
inserted on the proximal end of the first phalanx 
of the fifth finger. 
Metacarpo-phalangeus I. digits V. (Adductor 
digiti minimi). Springs from the metacarpal bones 
of the second and third fingers and is inserted on the 
radial side of the first phalanx of the fifth finger. 
THE ABDOMINAL MUSCLES 
Obliquus Abdominis Externus (Grand oblique, 
Aeusserer schiefer Bauchmuskel, Obliquus exter- 
nus, Obliquus externus +internus + Serrati, Oblique 
descendens). Springs, with a flat prong, from the 
uncinate processes of the true ribs, thence it 
extends as a tendinous aponeurosis, near the 
lateral boundary of the ileo-costalis muscle, caudal- 
ward to the region of the twenty-third (crocodile) 
vertebra. From this fairly straight line of origin 
the muscle takes a sharply distoventral course and 
is inserted, at least in part, on the outer surface of 
the sternal part of the ribs of the tenth to sixteenth 
vertebrae, but does not reach the mid-ventral line. 
Under this chief part of the outer layer of the 
abdominal muscle lies a second, more band-like 
muscle mass which is also strong but of consider- 
ably less extent. It takes its origin from the 
outer surface of the middle third of the ribs. In 
the region of the twentieth vertebra it fuses with 
the upper layer, but inwardly reaches nearer the 
median line than the upper layer. 
