16. CROTALIDM 



the head elevated, the tail projecting and rapidly vibrating. 

 At the approach of the intended victim, the serpent, by 

 sudden contraction of the muscles upon the convexity of the 

 curves, straightens out the anterior portion of the body, and 

 thus darts forward the head. At this instant, the jaws are 

 widely separated, and the back of the head fixed firmly upon 

 the neck. With the opening of the mouth, the spheno-pala- 

 tines contract, and the fangs spring into position, throwing 

 oflF the sheath as they leap forward. With delivery of the 

 blow and penetration of the fangs, the lower jaw closes 

 forcibly, the muscle that executes this movement causing 

 simultaneously a gush of venom through the tubular tooth 

 into the wound. There are also some secondary actions, 

 though all occur at nearly the same instant. The mouth, 

 fixed at the wound, drags upon it with the whole weight of 

 the snake's body. This dragging motion is accompanied by 

 contraction of the ectopterygoid and spheno-palatine muscles, 

 which ordinarily fold back the tooth j but the fang being 

 at this moment engaged in the flesh, the action of the 

 muscles only causes it to bury itself deeper, and thus enlarge 

 the puncture. The train of action seems to be, the reaching 

 of the object, the blow, the penetration, the injection of the 

 poison, and the enlargement of the wound. These actions 

 completed, the serpent loosens its hold by opening the jaws, 

 and disengages itself, sometimes not without difficulty, 

 especially when the bitten part is small and the numerous 

 small teeth have caught. The head is withdrawn, the fangs 

 folded, the mouth closed, and the former coiled attitude of 

 passive defense is resumed. 



"While the venomous properties of these reptiles, not 

 easily overrated, should suffice to ensure due caution in cap- 

 turing or killing them, it is as well to remember that the 

 utmost range of a rattlesnake's blow is less than its own 

 length. They may readily be captured alive by pinning down 



