VESTIGIAL ORGANS
mammals (Fig. 4). These bones are completely embedded in the substance of the whale and are apparently quite functionless. They are therefore good examples of vestigial organs.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/2/24/Creation_by_Evolution_%281928%29_p039_homology_between_human_hand_and_horse_forelimb.png/180px-Creation_by_Evolution_%281928%29_p039_homology_between_human_hand_and_horse_forelimb.png)
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.
The front and hind legs of the horse also contain vestigial parts. If the skeleton of the front leg of a horse is examined it will be found to be composed of many bones like those in the human arm. Buried in the flesh below the shoulder of the horse is a single bone corresponding 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 ]