HO THE EVOLUTION OF MAN. 



as have the power of erecting the ears, "because the form 

 and position of the ear may thus be materially altered, in 

 order to take in the various waves of sound in the best 

 possible manner. In Man, however, and in other animals 

 not possessing the power of pricking up the ears, the 

 muscles, though present, are useless. As our ancestors long 

 ago discontinued to make use of them, we have lost the 

 power of moving them. Again, there is in the inner corner 

 of our eye a small crescent-shaped or semi-lunar fold of skin; 

 the last remnant of a third inner eyelid, the so-called nicti- 

 tating membrane. In our primitive relatives, the Sharks, 

 and in many other Vertebrates, this membrane is highly 

 developed, and of great use to the eye ; but with us it is 

 abortive and entirely useless. On the intestinal canal we 

 have an appendage, which is not only useless, but may 

 become very injurious, the so-called vermiform appendage 

 of the caecum. This little appendage of the intestine not 

 infrequently causes fatal disease. If in the process of 

 digestion, by an unlucky accident, a cherry-stone or some 

 similar hard body is pressed into its narrow passage, a 

 violent inflammation ensues, which usually causes death. 

 This vermiform appendage is not of the slightest use in our 

 organism ; it is the last and dangerous remnant of an organ, 

 which was much larger in our vegetarian ancestors, and was 

 of great use to them in digestion ; as it is still in many 

 herbivorous animals, such as Apes and Rodents, in which 

 it is of considerable size, and of great physiological im- 

 portance. 



Other similar rudimentary organs exist in us, as in all 

 higher animals, in different parts of the body. They are 

 among the most interesting phenomena with which Com- 



