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 an}i:hing 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 m 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 



