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of motion by no means compatible with its structure or cause of 

 action. 



I have already observed — and it may partly account for the 

 reputed quickness of the tongue — that at one period of the elongation 

 the rapidity, even in my chameleons, was' such as might justly 

 be compared with that of an arrow, but then it was only momentary, 

 and observed during a very short stage of the process. The progress 

 of the tongue on leaving the mouth was at first slow, and became 

 gradually accelerated as it approached near the prey, when it shot 

 forwards with remarkable quickness — a mode of proceeding much 

 inore likely to ensure success than if it had advanced with uniform 

 rapidity from the commencement. This quickness perhaps equalled 

 that which is attributed to the organ when in vigour ; but it was 

 only manifested after its gradual repletion with blood, and when a 

 slight impulse was sufticient to produce it. 



Should the explanation which I have given of the mechanism of 

 the chameleon's tongue, founded on its structure and appearance 

 during life, be admitted as applicable to the animals on which I 

 have made my observations, it may be likewise to all, however 

 vigorous, for the same cause must equally produce the elongation 

 whether the act be rapid or slow — whether it take place during a 

 state of activity or weakness. 



Several individuals who have witnessed the change of colour and 

 mode of feeding of my chameleons, can corroborate the accuracy of 

 the above statements ; but I shall particularly refer for evidence of 



