428 CORPOREAL CHARACTERISTICS OF MAN. 



would be lost to us as grand instruments in the exercise of our 

 mental superiority. Quadrupeds have a strong ligament at the 

 back of the neck to sustain the head ; in us there is no such thing, 

 and our extensor muscles at the back of the neck are compa- 

 ratively very weak.* They have the thorax deep and narrow, 

 that the anterior extremities may lie near together and give more 

 support 3 the sternum too is longer, and the ribs extend con- 

 siderably towards the pelvis to maintain the incumbent viscera ; 

 our thorax is broad from side to side, that the arms being thrown 

 to a distance may have greater extent of motion, and narrow 

 from the sternum to the spine ; and the abdominal viscera, press- 

 ing towards the pelvis rather than towards the surface of the 

 abdomen in the erect attitude, do not here require an osseous 

 support. The pelvis is beautifully adapted in us for supporting 

 the bowels in the erect posture ; it is extremely expanded, and 

 the sacrum and os coccygis bend forwards below : in brutes it 

 does not merit the name of pelvis ; for, not having to support 

 the abdominal contents, it is narrow, and the sacrum inclines 

 but little to the pubes. The nates, besides extending the pelvis 

 upon the thigh bones in the erect state of standing or walking, 

 allow us to rest while awake in the sitting posture, in which, the 

 head and trunk being still erect, our organs of sense have their 

 proper direction equally as in walking or standing : were we 

 compelled to lie down like quadrupeds, when resting during the 

 waking state, the different organs of the face must change their 

 present situation to retain their present utility, no less than if we 

 were compelled to adopt the horizontal progression ; and, con- 

 versely, were their situation so changed, the provision for the 

 sitting posture would be comparatively useless. 



* 



* As the head is connected with the trunk farther back in brutes than in 

 us, the small length of lever between the occipital foramen and the back of the 

 head, and the length of the head below the foramen, require all this power ; 

 but even in us much more upholding power than we have at the back of. the 

 neck would be required for all-four progression, as the head would no longer 

 rest upon the spine. 



