MUSCULAR SYSTEM OF THE RED HOWLING MONKEY 



55 



(fig. 11), and from the deep surface of the caudal seven or eight costal 

 cartilages. They run transversely to the ventral midline ending on an 

 ai)oneurosis along a line corresponding roughly to the semilunar of the 

 external oblique in the three males. The female had muscular fibers of 

 very little length which ended shortly after their origin making the 

 aponeurosis a broader layer. This lamina is fused very intimately to 

 that formed by the internal oblique with which it shares its ending. 

 It always passes behind the rectus abdominis, but, in one male (fig. 



% 



y^ 



3) 



b) 



M ^.5. 



Figure 18. — a-c, Cross sections of the formation of the rectus sheath: (o.e.a., m. obliquus ex- 

 ternus abdominis; o.i.a., m. obliquus internus abdominis; t.a., m. transversus abdominis). 



