INTRODUCTION. 



humerus, as far as possible from its union with the scapula : therefore 

 their action is to bring the arm backward, the palms of the hands being 

 turned obliquely outward. The muscles of the scapulae are distinguished 

 rather for length than volume : length imparts rapidity of motion ; 

 volume gives power. The muscles of the scapulae are elevators of 



Skeleton of the Mole. 



the humerus ; and the nature of their duty does not so much require 

 power as celerity, in order that the action of burrowing may proceed 

 with the least lapse of time between each stroke. A glance at the ske- 

 leton of this animal is sufficient to shew, that its whole power is concen- 

 trated in the anterior extremities, and, in this respect, it exceeds all other 

 burrowing animals. 



A comparison of the limbs of the Mole with those of other animals of 

 similar habits, will be interesting. From these, the Armadillo, one of the 

 Edentata, may be selected. This animal, not, indeed, a miner par excel- 

 lence, like the Mole, is yet a burro wer in the earth, excavating deep 

 retreats for itself, in which it passes a great portion of its existence : 

 unlike the Mole, however, it does not follow its prey under ground, but 

 comes abroad to feed. 



The general strength and solidity of the bones, composing the skele- 

 ton of the Armadillo (fig. 86), cannot fail to excite attention ; while those 



Skeleton of the Nine-handed Armadillo. 



of the fore limbs display, very admirably, the characteristics which denote 

 its habits and modes of life. The expansive convex scapula, a, with a 



