PHYSIOLOGY, AND PATHOLOGY OF THE CHIMPANZEE. 361 



The tibialis posticus arises from the lower part of the head and 

 upper part of the body of the fibula anterior to the flexor longus 

 hallucis, from the upper half of the interosseous membrane, the 

 upper half of the tibia external to the popliteal line and its 

 downward continuation and from the septum between it and the 

 long flexors. It is inserted much as in Man, only the scaphoid 

 here has no definite tubercle. 



The peroneus longus arises from the anterior half of the outer 

 surface of the head of the fibula, the antero-lateral surface of the 

 fibula to within an inch of the malleolus, the upper half of the 

 anterior peroneal septum, the posterior peroneal septum and 

 the fascia over it. The tendon passes behind the outer malleolus 

 and external to the peroneus brevis, and from there on it is as 

 in Man. 



The peroneus hrevis arises from the lower half of the antero- 

 lateral surface of the fibula down on to the lateral malleolus, the 

 anterior peroneal septum and the fascia over it. The tendon 

 goes behind the outer malleolus and is inserted into the projecting 

 base of the fifth metatarsal. An inch below the malleolus the 

 tendon gives a slip to the dorsal expansion on the dorsum of the 

 proximal phalanx of the fifth toe. 



The extensor hrevis digitorum arises from the outer side of the 

 upper surface of the os calcis anterior to the posterior facet, the 

 dorsal calcaneo-cuboid ligament and the lower border of the ex- 

 ternal annular ligament. Its four fleshy bellies end in slender 

 tendons to the four inner toes. The most medial tendon has an 

 expanded insertion into the base of the dorsum of the proximal 

 phalanx of the hallux. The other three join the dorsal extensor 

 expansions, thereby being inserted into the bases of the second 

 and third phalanges. 



The flexor hrevis digitorum arises as in Man. It divides into 

 two tendons, the lateral one to the third toe being joined by a 

 slip from the long flexor. The medial one goes to the second toe. 

 Insertion as in Ma.n. 



The abductor hallucis arises as in Man, and it also receives 

 fibres from the inner side of the foot (internal annular ligament, 

 scaphoid, entocuneiform and capsule of the metatarso -phalangeal 

 joint). It is inserted into the inner aspect of the capsule of the 

 first metatarso-phalangeal joint and the base of the first phalanx, 

 with the interposition of a sesamoid bone. A small slip passes 

 to the shaft of the first phalanx. 



The abductor minimi digiti arises as in Man. It is inserted 

 into the outer side of the projecting base of the fifth metatarsal 

 (abductor ossis metatarsi quinti of Hepburn), the inner side of 

 the base of the fifth metatarsal, the outer side of the plantar 

 aspect of the capsule of the metatarso-phalangeal joint and base 

 of the proximal phalanx, and the outer side of the shaft and the 

 dorsal expansion on the first phalanx. Hepburn (24) mentions 

 the latter in the Orang. 



The flexor brevis hallucis has two bellies. The deep inner one 



