258 NATURAL THEOLOGY. 



the jaw presses its root against the bag under- 

 neath ; and the force of this compression sends 

 out the fluid with a considerable impetus through 

 the tube in the middle of the tooth. What more 

 unequivocal or eftectual apparatus could be de- 

 vised for the double purpose of at once inflicting 

 the wound and injecting the poison ? Yet, though 

 lodged in the mouth, it is so constituted, as, in its 

 inoffensive and quiescent state, not to interfere 

 with the animal's ordinary office of receiving its 

 food. It has been observed, also, that none of 

 the harmless serpents, the black snake, the blind 

 worm, iS^:c., have these fangs, but teeth of an equfel 

 size ; not moveable as this is, but fixed into the 

 jaw. 



II. In being the property of several different 

 species, the preceding example is resembled by 

 that which I shall next mention, which is the hag 

 of the opossum. This is a mechanical contrivance, 

 most properly so called. The simplicity of the 

 expedient renders the contrivance more obvious 

 than many others, and by no means less certain. 

 A false skin under the belly of the animal forms a 

 pouch, into which the young litter are received at 

 their birth ; where they have an easy and constant 

 access to the teats ; in which they are transported 

 by the dam from place to place ; where they are 

 at liberty to run in and out ; and where they find 

 a refuge from surprise and danger. It is their 

 cradle, their asylum, and the machine for their 

 conveyance. Can the use of this structure be 



