KEPTILIA. 559 



poral muscle (d) 9 which is attached to a thin aponeurotic line (e). 

 The greater portion of the fibres of this muscle take their origin 

 from the capsule of the secreting apparatus, which they partially 

 envelope ; and then winding round all the posterior part of the 

 gland, and passing behind the commissure of the lips, the lower 

 part of the muscle is firmly implanted into the lower jaw very far 

 anterior to the angle of the mouth. The process of the temporal 

 muscle which thus surrounds the gland is very thick and strong, so 

 that it is easy to imagine with what force the poison will by this 

 mechanism be injected into the wounds inflicted by the fangs, seeing 

 that the same muscles which close the jaw at the same time com- 

 press the bag of venom with proportionate energy. 



Behind the large poison-fang in use, the capsule that encloses it 

 generally contains the germs of several others, ready to supply its 

 place should the former be broken off; and, on the event of such 

 an accident, one of these supplementary teeth soon becomes consoli- 

 dated with the superior maxilla, and adapted in all respects to take 

 upon itself the terrible office of its predecessor. 



(616.) Dreadful as are the means of offence thus conferred 

 upon the poisonous serpents, it is impossible to avoid noticing in 

 this place that admirable provision of Nature, which, in one genus 

 at least, serves to give timely warning of the vicinity of such dan- 

 gerous assailants. We need merely mention the rattle of the 

 Rattle-snakes (Crotalus) ; an organ, the intention of which is so 

 obvious, that the most obtuse cannot contemplate it without at 

 once appreciating the beauty of the contrivance. This singular 

 rattle is formed of numerous horny lings, that are in fact merely 

 modifications of the general scaly covering of the reptile, so loosely 

 articulated together, that the slightest movement of their formida- 

 ble possessor is betrayed by the startling noise produced by the 

 collision of the different pieces composing the organ ; even when 

 at rest, the creature announces by rapid vibrations of the tail the 

 place of its concealment, apparently to caution the inadvertent in- 

 truder against too near an approach. 



(617.) In the grand police of Nature, the scavengers are by no 

 means the least important agents. In hot climates especially, 

 where putrefaction advances with so much rapidity, were there not 

 efficient and active officers continually employed in speedily re- 

 moving all dead carcases and carrion, the air would be perpetually 

 contaminated with pestilential effluvia, and entire regions rendered 



