INSECT-EATERS 69 



passage for the body. Being wedge-shaped, it can by powerful forward 

 pushes be easily driven through the soil. This wedge-shaped form of 

 the head is due to the elongation of the nose into a snout or proboscis. 

 Though rendered firm by the presence of cartilage, this proboscis — as 

 can be easily proved in the living or dead animal — nevertheless remains 

 pliant and movable. It follows accordingly that the head cannot be used 

 as a boring instrument in a hard or still less a stony soil. Here the 

 digging feet alone can operate. These, however, do not extend beyond 

 the front of the snout in the extended animal, as it is indispensable that 

 they should for carrying out their work. Accordingly, to enable the 

 hands to precede the head in hard soil, the head is drawn very far back, 

 further, in fact, than is possible in the case of any other mammal. (This 

 can be very clearly shown in a dead animal by pressing the head.) 



Further, the head also acts as a shovel. Having previously made 

 a passage opening on the surface, the animal, by powerful pushes 

 of the head, throws up from its underground tunnel any loose earth 

 which has accumulated there. This explains the origin of a molehill. 

 While thus occupied the cautious creature, however, always takes care 

 to keep its body covered with a layer of loose earth from 6 to 8 inches 

 in depth. 



3. The hind-limbs take no part in the work of burrowing. They are, 

 therefore, much weaker than the fore-legs, and have the usual form. 

 Treading with the whole sole of the foot for the sake of friction, they 

 push — 



4. The cylindrical body forwards. This shape is of great importance 

 to a burrowing animal, for the size of the burrow depends on the greatest 

 thickness at any part of the body. And if the body were flattened either 

 laterally or horizontally it could not turn round on its axis. (What is- 

 the shape of other burrowing animals known to you ?) 



5. The neck is so short as to be quite imperceptible from outside. 

 The result is a considerable saving of force, for a long neck, by being 

 deflected when the head is thrust forward, would involve a considerable 

 waste of force. 



6. When we consider how the mole alone and unaided forces his way 

 through the solid earth, which man can only loosen by the aid of sharp 

 iron implements, and how rapidly it progresses in loose earth, we must 

 conclude that it is possessed of simply stupendous strength. Indeed, the 

 mole is a giant among dwarfs. For putting its digging and scraping 

 tools in action, especially powerful muscles are developed in the anterior 

 part of its body. These are attached to the long shoulder-blades, the 

 strong clavicles and bones of the arm, and the high bony crest of the 

 sternum. (Compare with birds.) 



