It has been argued by Sir Richard Owen and others that the position of the great toe converts the foot of the higher apes into a hand, an extremely important distinction from man; but against this Professor T.
With regard to the evolution of marsupials and placentals, it has been pointed out that the majority of modern marsupials exhibit in the structure of their feet traces of the former opposability of the thumb and great toe to the other digits; and it has accordingly been argued that all marsupials are descended from arboreal ancestors.
The foot resembles that of the other lemurs in its large opposable great toe with a flat nail; but all the other toes have pointed compressed claws.
In characters of such importance as the structure of the hand and foot, the lower apes diverge extremely from the gorilla; thus the thumb ceases to be opposable in the American monkeys, and in the marmosets is directed forwards, and armed with a curved claw like the other digits, the great toe in these latter being insignificant in proportion.
Again and again it has been proved that the human great toe can be by constant practice used as a thumb; artists exist who have painted pictures grasping the brush with their toes, and violinists have been known to play their instruments in the same manner.