FOOT OF THE OSTRICH. 



245 



placed farther forward than when the hind toe is 

 weak, or wanting-, or articulated higher on the tarsus 

 than the other toes, in order that the axis of the body 

 may be carried horizontal. Feet also combine other 

 actions, such as scraping in the earth or swimming, 

 with their action of progressive motion upon land, 

 and this farther embarrasses us in our attempts to 

 classify them ; so that, without writing almost as 

 many volumes as there are kinds of feet, little else 

 can be done than simply to mention the description 

 of surface and motion, and notice the form of the foot. 

 For swift motion over arid surfaces, covered with 

 dry sand, the foot of the ostrich is best adapted. 



Ostrich. 

 This foot has only two toes, bothlhick and strong, 

 the inner short, and without any claw; the outer 

 longer, and furnished with a broad blunt one. The 

 tarsus is very thick as well as long, and the muscles 

 on the tibia are large, and extend as far down as the 

 tarsal joint. The joints have little lateral motion, 

 but the progressive motion is extensive, and the foot 



