MUSCULAR SYSTEM OF THE RED HOWLING MONKEY 



61 



the dorsum of the jjenis. The insertion is on the deep fascia of the 

 penis along the dorsal midline. 



M. ischiocavernosus (fig. 21) : It is larger than the bulbospongiosus. 

 Origin is from the inner surface of the body of the ischium and the 

 lower pubic ramus from where its fibers pass ventrally covering the 

 corpus cavernosum. They spiral around the crus to reach the dorsum 

 of the penis behind the bundles of the bulbospongiosus. Insertion 

 is on the deep fascia of the penis and the pubic body near the 

 symphysis. 



M. ischiourethmlis (fig. 21): Some fibers of the former muscle 

 diverge medially to end on the ventral and lateral part of the urethra 



Figure 22. — Muscles of the pelvic floor (1, m. psoas minor; 2, n. obturatorius; 3, m. ilio- 

 caudalis; 4, m. pubocaudalis; 5, m. retractor recti et urethrae; 6, m. obturatorius internus; 

 7, m. sphincter ani externus; 8, attachment of m. iliocaudalis to hemal arches 4 and 5; 9, 

 m. caudoanalis of the right side, origin not shown; 10, attachment of m. pubocaudalis to 

 hcmal arch 3; 11, m. caudorectalis; 12, m. caudoanalis of the left side arising from hemal 

 arch 1; 13, origin of m. retractor recti ct urethrae). 



