INSECTIVOROUS MAMMALIA. 465 



into a sharp cutting edge. The carpal bones and 

 the phalanges of the fingers are very much com- 

 pressed ; but they are furnished with large nails, 

 which compose more than half the hands ; and 

 they are expressly constructed for digging, being 

 long, broad, and sharp at the extremities. The 

 sternum has a large middle crest, and is prolonged 

 at its extremity into a sharp process, having the 

 figure of a ploughshare, thus affording an extensive 

 surface of attachment for the large pectoral muscles, 

 from which the limb derives its principal force. 

 The head terminates in front by a pointed nose, 

 which is armed at its extremity with a small bone, 

 intended to assist in penetrating through the ground. 



While all this attention has been paid to the de- 

 velopement of the anterior part of the body to which 

 these instruments specially contrived for burrowing 

 are affixed, the hinder part is comparatively feeble, 

 and appears stinted in its growth, and curtailed of 

 its fair proportions. The pelvis is exceedingly 

 diminutive, being reduced to a slender sacrum ; 

 and it is thrown far back from the abdomen, to 

 which it could give no effectual protection. Hence 

 the animal, when above ground, walks very awk- 

 wardly, and is unable to advance but by an irre- 

 gular and vacillating pace. 



The only quadrupeds which resemble the mole in 

 the perfect adaptation of their structure to the pur- 

 poses of burrowing, are the Wombat and the Koala, 

 which are among the many extraordinary animals 

 inhabiting the continent of Australia. Their hind 

 legs are constructed in a manner very much re- 

 sembling the human fore-arm.* 



* See Home, Lectures, &c. i. 134. 

 VOL. I. H H 



