io 4 PHYSICAL BASIS OF CIVILIZATION 



have not feet (distinguished by the hallux forming 

 a natural fulcrum in walking), but hands, on theii 

 lower or posterior extremities ; nor is their foramen 

 magnum situated, as in man, as it must be for con- 

 venient and natural uprightness, a little behind the 

 centre of the base of the skull. It is, therefore, more 

 natural and far more easy for them to be and move 

 about, on all fours. Their pregnant females, in this 

 latter attitude, are no more liable to injury from 

 falls and stumbles, and their vitals no more exposed, 

 than those of ordinary quadrupeds or baboons. The 

 extraordinary great capacity of the thoracic cavity 

 of these animals, and the massive strength of the 

 bony structures surrounding it, and the adaptation 

 of the pelvic bones and ligaments to keeping the 

 uterus securely and comfortably in position give 

 them an advantage in the struggle for existence: 

 to which another must be added, viz., their long, 

 strong arms and limbs, supplied at the extremities 

 with hands, specially adapted to grasping and 

 holding on to branches, which give them chances 

 of escape only surpassed by flying creatures. And 

 these latter are at a disadvantage compared with 

 them, for it requires constant and great effort to 

 sustain themselves in the air ; but apes and anthro- 

 poids can be at rest and comfortable after escaping 

 to a place of security in the trees, and can live and 

 feed and breed there. Their hairiness and tough 

 hides protect them against injuries from accidents, 

 violence, changes of temperature or climate, and 



