MUSCULAR SYSTEM OF THE RED HOWLING MONKEY 



161 



absent in the left side of one male. It lies along the peroneal half of 

 the plantar surface of the tarsus. Origin is by a mixture of fleshy and 

 tendinous fibers from the lateral side of the calcaneal tubercle. Its 

 compressed belly receives additional fibers from the plantar apo- 

 neurosis. The medial border of the muscle is next to the caput super- 

 ficialis of the short digital flexor. It covers the quadratus plantae. 

 As the abductor approaches the tarsometatarsal joint of the fifth 

 toe, it splits into two tendons. One tendon, which is short, round, and 



M.k/S. 



Figure 49. — Distribution of tendons of m. flexor digitorum brevis. 



