THE EVOLUTION OF MAN 197 



a change which is compensated in part by the broad, basin-hke 

 pelvis. 



The leg bones of man are modified to a relatively slight extent, 

 but the femur is much straighter than in arboreal primates or 

 quadrupeds. The foot is completely without the grasping power 

 found in the primates, and is therefore much different from the 

 hand which retains an opposable thumb. Its most interesting 

 character is the predominance of the big toe. Specialization of 

 the appendages usually n^sults in emphasis upon one digit, but 

 the most prominent digit of the primitive pentadactyl appendage is 

 the third. In the horse we have noted the development of this one 

 to the exclusion of all others. IVIan therefore is unusual in the 

 great development of his first toe. A logical explanation is found 

 in the significance of this digit in an arboreal animal. Develop- 

 ment as a digit opposable to all others would find it already the 

 most specialized of all when its possessor became terrestrial, and 

 would provide the basis for further emphasis upon it during ter- 

 restrial life. In connection with its dominance, all other toes are 

 reduced, and the little toe is even rudimentary in some races. 

 Jones cites the Malays and Nubians as extreme examples. In these 

 peoples the fifth toe is said to be stumpy and often without a 

 nail. The foot has an arched skeleton, apparently for the absorp- 

 tion of shocks which would otherwise be transmitted through the 

 entire longitudinal axis of the body. 



A final specialization of man, the loss of hair from most of the 

 body, and his delicacy of skin are probably associated with the 

 development of intelligence. Matthew points out that man's 

 retention of hair on the ventral surface of the body, where it is 

 thinnest in other animals, is exactly what might be expected of 

 long use of protective clothing. A simple garment, such as a skin 

 thrown over the shoulders and tied around the waist, would pro- 

 tect just those parts of the body where the hair is most completely 

 lost. It is significant that monkeys in our zoos make use of cover- 

 ing in this way. A number were wintered in outdoor cages as an 

 experiment, and were provided with gunnj^sacks as protection 

 against the cold. When evening came, each monkey helped him- 

 self to a sack, climbed to his perch, threw the sack over his shoul- 

 ders and settled down for the night. 



In most of his structures man is a primitive animal. In those 

 mentioned, however, he is definitely specialized, and his specializa- 



