76 FIRST LESSONS IN ZOOLOGY 



and bones of the human hand and arm with those of 

 the fore hmb of other animals we find an advance in 

 complexity over the fin of a fish or the fore limb of a 

 salamander or even the fore ley of a dog, although all are 

 made up on the same plan and out of the same elements. 

 If we now go further and compare the organs of motion 

 in the human body with the means of motion in Amoeba 

 we see what a wonderful advance the highest animal 

 exhibits over the lowest both in structure of the motor 

 organs and in the possibilities of movement. 



