136 LECTUEE VI. 



where in the animal world, as Milne-Edwards has most convinc- 

 ingly shewn, the division of labour is an index of perfection. 

 An animal which has four limbs apparently destined for the 

 same end, as is the case with the horse and the sheep, is in 

 this respect inferior to the animal in which the anterior limb 

 is at the same time a prehensile organ, as in the squirrel and 

 the beaver. The ape, whose four limbs are provided with 

 hands, stands in this respect a step below man, in whom the 

 legs are exclusively adapted for locomotion, and the hands 

 exclusively prehensile organs. The more special the function 

 of an organ, the more perfect it is : the greater the number of 

 purposes an organ has to subserve in the animal economy, the 

 more imperfectly will they be performed. Hence, though the 

 hand is in every respect a more perfect organ than the merely 

 locomotive foot, the multipHcation of hands must still be con- 

 sidered a mark of defective organisation, since each of these 

 hands is at the same time a locomotive and prehensile organ, 

 whilst the restriction of both these functions to two different 

 sets of organs is a step towards perfection. 



The breadth of the hips, and the pelvis, which forms their 

 osseous support, is still more connected with erect stature than 

 the width of the thorax. The bowels suspended in the thoracic 

 and abdominal cavities press downwards. The pressure of the 

 thoracic contents is partially neutralised by the diaphragm 

 which separates the cavity of the chest from that of the abdo- 

 men ; but the whole weight of the intestines, including liver 

 and spleen, rests upon the pelvis. This latter expands like a 

 dish j the iliac bones become broad and flat, excavated above 

 and arched downwards and outwards ; so that the name " pel- 

 vis," or basin, is perhaps one of the best chosen in anatomy. 

 In animals, on the other hand, the pelvis bears but little of the 

 weight of the bowels ; and just that part which does bear it, 

 namely the symphysis pubis, is in man least concerned in this 

 respect. The weight rests, in the animal, upon the central 

 line of the chest and the belly, the pelvis chiefly serving as the 

 fulcrum of the hind legs. Hence the pelvis presents no ex- 

 tended surfaces, but becomes long and narrow ; the parietal 

 parts resemble the shoulder-blades, which serve as supports to 



