ANATOMY OF THE ANTHEOPOID APES. 215 



calcis ; the muscular fibres continue to within a quarter of an inch of the actual 

 insertion. 



The plantaris muscle appears to be totally absent. 



(27) PopUteus. — The muscle runs obliquely across under the surface of the knee 

 from the external condyle of the femur to the tibia. Its insertion on to the latter 

 measures an inch and a quarter in length. 



(28) Flexor longus {perforatus) digitorum pedis. — The origin of this muscle extends 

 from just below the head of the tibia and the insertion of the popliteus to more than 

 halfway down the bone. It is connected also with the origins of the two remaining 

 long flexors. It divides beyond the ankle-joint into three tendons, which go to 

 digits II., III., and v. 



(29) Flexor hrevis is a broad strap-shaped muscle arising from the calcaneum ; 

 beyond the trifurcation of the flexor longus tendon it divides into three tendons, one 

 of which joins the superficial (perforated) tendons of digit iv., the other two supply 

 digits II. and lii. ; these branches become the perforated tendons of those digits, being 

 quite indistinguishable in their characters from the -perforated tendons of adjacent 

 digits. The tendon supplying the second digit does not become fused to the super- 

 ficial long tendon, as it does in the case of that supplying the fourth digit ; what 

 happens is that the tendon of the flexor accessorms takes the place of the superficial 

 tendon, which the tendon of the real superficial tendon perforates ; the former runs to 

 the last phalanx of the digit as if it were a branch of the flexor profundus. The same 

 thing occurs with the tendon supplying the third digit, only that here the perforating 

 tendon is really the deep flexor. 



(30) Flexor profundus digitorum. — The origin of this muscle is from the outer con- 

 dyle of the femur, from the fibula to beyond its middle point, and from the septa 

 between itself and adjacent muscles ; it divides at the middle of the sole of the foot 

 into two tendons, which supply digits iii. and iv. 



(31) There are four lumbricales, as in the hand : that supplying the index arises 

 only from the flexor perforatus of that digit ; the others are attached partly to the 

 deep and partly to the superficial flexors, binding them together in a complicated 

 fashion, of which there is only a trace in the hand. 



(32) Tibialis posticus. — This muscle lies deep of the other long flexors, and is 

 smaller than either of them ; its tendon is inserted on to the wrist. 



(33) Abductor hallucis is a fleshy muscle arising from the calcaneum ; it ends in a 

 tendinous expansion inserted on to the phalanx of the great toe. 



(34) Abductor minimi digiti is a fusiform muscle, also arising from the calcaneum ; 

 it divides into two muscles just before the head of the metatarsal ; these soon become 

 long tendons, which are inserted on to the distal extremity of the metatarsal of the 

 little finger and on the proximaJ end of the first phalanx ; the latter tendon is the 

 larger. 



