68 TEXT-BOOK OF ZOOLOGY 



the loose earth behind it. The structure of these limbs is accordingly 

 quite different to that of the hind-limbs, which are much weaker, and in 

 which the whole sole of the foot is used for walking. 



(a) The fore-limbs do not, as in most other mammals, point down- 

 wards, but away from the body laterally and horizontally. 



(b) The hands are very broad, and their inner surfaces, which are 

 hairless, are directed posteriorly. Their breadth is still further increased 

 by a sickle-shaped bone placed on the outside of each of the thumbs, the 

 so-called " falciform bone." The short toes are for the greater part of 

 their length united by webs. They have long broad nails sharpened at 

 the points. 



(c) The mole scratches or scrapes loose the earth with its feet in the 



Anterior Half of the Skeleton of the Mole. 

 (One and a half times natural size. ) 



E.k., Nasal cartilage; Au., eye socket; 8ch., shoulder-blade; S.b., clavicle (lateral view); 

 O., humerus ; Sp., ulna ; E., radius ; S.k., "scraper" ; B., sternum. 



same way as we should scrape off a portion from some solid object with 

 a spoon. In the latter operation, it is most advantageous to hold the 

 handle of the spoon as short as possible (why ?), and accordingly in the 

 case of the animal the hand has a very short stalk ; i.e., the upper and 

 lower arms are very short and quite hidden within the body, the hand 

 only projecting out of the fur. The bones of the arm are of extra- 

 ordinary strength, and impart great firmness to the stalk of the hand. 



(d) The clavicles are strong, and afford firm points of attachment to 

 the fore-limbs. (Compare with the bat and bird.) 



2. In loose and especially sandy soil the head assists in forcing a 



