353 



ELEMENTARY ANATOMY. 



[LESS. 



own class, but even in that they may be reduced to a mini- 

 mum, as in the Horse. The foot may be largely developed, 

 with four elongated and prehensile digits, and yet have very 

 little muscular tissue, as in Birds. Some leg muscles may be 

 present, and yet there may be no foot-muscles, as is the case 

 in Lialis Burtonii. 



The abductor pollicis pcdis seu hallucis is often absent, as 

 in the Horse ; yet it exists in both Reptiles and Batrachians, 

 as, e.g., in the Chameleon and the Frog. 



F.l.d 



FIG. 319. MUSCLES AND TENDONS OF SOLE OF HIND FOOT OF HYRAX. 



Tack, tendo Achillis; Flh, tendon of flexor longus hallucis; FM, tendon of flexor 

 longus digitorum ; Fbd, flexor btevis digitorum, with one of its perforated 

 tendons cut through and the whole muscle drawn to the one side to expose the 

 deep flexor tendons; A, accessorius ; L, lumbncales. 



Flexor brevis digitorum. This may be absent, and then 

 is often replaced "by the plantaris, as, e.g., in the Pig and 

 Rabbit. It may arise exclusively from the surface of the deep 

 flexor tendon, as in Nycticebus, and in no member of man's 

 order but man himself does it arise from the os calcis only. 



