42 SAVAGE SURVIVALS 



adopt a wriggling or creeping style of locomotion. 

 The legs went out of use as a result. And this 

 change in the life of these reptiles took place so 

 long ago that in all but a few cases every vestige 

 of limbs has disappeared. 



But there are many instances in the animal 

 kingdom where discarded organs still survive in a 

 dwindling and drying-up condition. These or- 

 gans, in the ancestors of the animals now possess- 

 ing them, were fully developed and useful, but, be- 

 cause of changes in habits or conditions of living, 

 they are now of no further use, and are gradually 

 dying out. Such organs are called Vestigial Or- 

 gans. 



Vestigial organs are simply organs without a 

 job. They are organs which haven 't anything to 

 do, and which are suffering the inevitable conse- 

 quences of long idleness. The amount of degen- 

 eration which any organ has undergone depends 

 on the length of time which has elapsed since it be- 

 came useless. Vestigial organs are departments 

 which have gone out of use, but which have not yet 

 gone out of existence. 



There are hundreds of vestigial organs in the 

 bodies of men and other animals. All the higher 

 species of animals have them. One of the best 

 known examples is the vermiform appendix in the 

 human body the useless organ which is removed 

 in cases of appendicitis. This organ in many of 

 the lower animals is a regular part of the diges- 

 tive system. Food enters it, and it secretes 



