VESTIGIAL ORGANS 



mammals (Fig. 4). These bones are completely embedded 

 in the substance of the whale and are apparently quite func- 

 tionless. They are therefore good examples of vestigial 

 organs. 



The front and hind legs of the horse also contain ves- 

 tigial parts. If the 

 skeleton of the front 

 leg of a horse is 

 examined it will be 

 found to be com- 

 posed of many 

 bones like those in 

 the human arm. 

 Buried in the flesh 

 below the shoulder 

 of the horse is a 

 single bone corre- 

 sponding to the one 

 in our upper arm. 

 Following this in 

 the horse is a pair 

 of bones duplicating 

 the two bones of 

 our forearm. Then 

 comes, in both the 

 horse and man, a 

 small group of 

 wrist bones. These 



are located in the horse at what is improperly called 

 its knee. From the so-called knee in the horse to its 

 hoof is a row of four stout bones, which correspond to the 

 four bones in line with the middle finger of man. 

 The first of these bones in the horse — that is, the one next 



[39] 



A 



B 



Fig. 5. — A, Palmar view of the skeleton 

 of the hand of man, showing the wrist 

 bones and the bones of the fingers ; B, Simi- 

 lar view of a part of the front leg of a 

 horse, showing wrist bones and the bones 

 corresponding to the middle finger of man. 



In the leg of the horse the vestigial 

 splint bones are represented in solid black, 

 and in the hand of man the corresponding 

 bones are also shown in black. 



