1 84 SNAKES. 



and others term it. For though the 'leap' Is not strictly 

 like the action of a frog or a grasshopper, or a man whose 

 two limbs act in concert and together, the result is the 

 same, — the reptile accomplishes a long distance with quick- 

 ness, decision, and aim. Professor Owen ^ calls it a saltatory 

 motion, 'the sudden extension of the coils of the body react- 

 ing upon the point of earth on which the tail presses, throwing 

 the serpent forward.' Sometimes, when the creature lies 

 closely coiled, the sudden unbending has the effect of a 

 spiral spring ; and occasionally, when the tail is brought 

 suddenly up to the head, and the serpent springs forward 

 again, and continues to do this in pursuit, as has often been 

 witnessed, the effect is that of a rolling hoop, and has given 

 rise to a belief among the ignorant that the reptile really 

 rolls along. 



One in America, known as the ' Hoop snake,' is reported 

 to ' roll down hill,' the idea originating possibly from the 

 optical illusion in consequence of the rapid changes of 

 position — an effect which we see in that amusing toy, the 

 zoetrope. 



The ' black snake ' of Australia, HopIocepJialus pseudechis^ 

 is one of the very active venomous kinds, whose motions 

 in pursuit or escape are almost like leaps, and present 

 the appearance of a hoop or circle. Reputed ' hoop snakes ' 

 are there also. The reptile rapidly extends itself to full 

 length, then brings up its posterior portion in a loop, and 

 so springs forward again, continuing to do this with amazing 

 rapidity. 



The most easy and natural convolutions of a snake are 



1 Anatonty of the Vertebrates, p. 260. 



