190 



STUDIES IN PHYSIOLOGY 



~one 



Anterior Appendages of Mammals. In the single group of 

 mammals we find most striking variations in the form and 

 functions of anterior appendages. 

 One would expect to find little in 

 common in the structure of a bat's 

 wing, a seal's fin, a giraffe's front leg, 

 and a lion's paw. Yet in all these 

 appendages there is a single humerus, 

 a radius, an ulna, and a number of 

 carpals, metacarpals, and phalanges. 

 Equally interesting is a. comparison 

 of the use made by mammals of the digits or fingers of the 

 anterior limb. Bears walk on the palm of the hand and 

 hence are called flat-footed. Elephants rest their weight on 

 the under surface of four of the five digits. The rhinoceros 



FIG. 84. Sectional View 

 of Foot of Horse. 



Cranium 



Azit 



-^-Cervical Vertebra* ( 7) 



Carpal 

 JUeto&trjMl Banes 



FIG. 85. Skeleton of the Horse. 



has three fingers or three toes on each appendage. In cows, 

 deer, and sheep we find but two fingers on each front foot, 



