gt CLASS MAMMALIA. 



qecause its articulation is strictly central in re- 

 ference to its own bulk. 



It would be impossible for man to walk con- 

 veniently on all fours, even if he desired to do 

 so: his feet being short, and almost inflexible, and 

 his thigh of too great length, would bring the knee 

 in contact with the ground : his shoulders being 

 too far separated, and his arms too far extended 

 from the central line would form a very ineffectual 

 support for the upper part of his body : the great 

 indented muscle which, like a girth in quadrupeds, 

 holds the trunk of the body suspended between 

 the shoulder-blades, is smaller in man than in any 

 individual among them: the head of man is also 

 heavier, both on account of the magnitude of the 

 brain, and the smallness of the sinuses, of the 

 bones of the cranium, and notwithstanding this, 

 the means of supporting it are weaker, for there 

 is neither a cervical ligament, nor such an arrange- 

 ment of vertebra as would prevent them from 

 bending forward; the consequence of this would 

 be, that in the position of a quadruped, man could 

 only keep his head in the same line with the spine ; 

 his eyes and mouth must infallibly be directed to 

 the ground, and he could scarcely see a step before 

 him, while, on the other hand, in reference to the 

 erect attitude, which is assuredly proper to man, 

 the position of these same organs is precisely what 

 it ought to be. 



As the arteries which supply the human brain 

 are not sub-divided, as in most quadrupeds, the 



