The Muscles 115 



IV. Rectus internus. On the inner surface 

 of the rectus ventraHs, from which it is separated 

 by the intervening aponeurosis of the rectus muscle, 

 appears a muscle lying on the outside of the dia- 

 phragmatic muscle. It extends as a broad band 

 from the breast to the anterior border of the os 

 pubis, with longitudinally directed fibers, to half 

 the width of the rectus ventralis muscle. 



Intercostales (Zwischenrippenmuskeln) . The 

 intercostal muscles in the Crocodilia are, in pro- 

 portion to the strength of the ribs, of slight struc- 

 ture; they extend only from rib to rib and are, 

 therefore, very short, though fairly thick. They, as 

 usual, consist of the outer muscles with a direction 

 like that of the external oblique, and of an inner 

 muscle extending in the opposite direction, i.e., 

 at right angles. The internal muscles are espe- 

 cially well developed in the breast region and pass 

 over into the internal oblique muscle. 



Quadratics Lumborwn (Carre des lombes, Vier- 

 eckiger Lendenmuskel, Psoas major). A strong, 

 thick muscle that springs from the inner surface 

 of the transverse processes and bodies of the last 

 six presacral and the first sacral vertebra. The 

 muscle diminishes as it passes in a caudoventral 

 direction and is inserted with a strong tendinous 

 band to the trochanter femoris. 



The Diaphragm (Diaphragmaticus, Zwerchfell, 

 Bauchf ellmuskel) . Closely inclosed between the 

 skin and muscle of the abdomen, in the Crocodilia, 



