of tJie Tongue of the Chameleon. 163 



ted my attention. In every part, but more especially between 

 the tubercles, it was so thin as to be almost transparent : and 

 its internal surface, when examined through a magnifying glass, 

 presented a complete net-work of fine vessels, rendered visible 

 by the dark blood which they contained. A portion of skin re- 

 moved from about the eyes, where in death it became dark, 

 even to blackness, displayed most satisfactorily the great abun- 

 dance of its vessels. 



These observations on the skin I have deemed it right to 

 make, as they appear to confirm the opinion entertained by 

 some physiologists, that its changes in colour are produced by 

 vascular turgescence, just as the increased redness in blushing is 

 caused by a rush of blood to the cheeks. The colour of the 

 blood appearing through the semitransparent skin, and modified 

 by the various permanent colours of that structure, is sufficient 

 to account for every diversity of tint which the chameleon ex- 

 hibits. I have been induced more particularly to offer these re^ 

 marks in this place, because, from the facts which I have no- 

 ticed regarding its tongue, I have been led to infer, that the pe- 

 culiarities of that organ are all referrible to the same general 

 cause, viz. vascular turgescence. 



By keeping my chameleons in an equable temperature of 

 about summer heat, I succeeded in preserving them both alive 

 for upwards of two months, during which I had ample oppor- 

 tunities of observing the action of their tongues in the prehen- 

 sion of the insects on which they fed almost daily. 



When a fly so maimed as not to be able to escape, but still 

 sufficiently vigorous to move its legs or wings, was so placed 

 that its fluttering might attract the chameleon's attention, the 

 animal advanced slowly until within tongue's reach of it, then 

 steadying itself like a pointer, sometimes stretching out its tail, 

 sometimes fixing it against an adjacent body, and directing both 

 eyes steadfastly on the prey, it slowly opened its mouth, and 

 suddenly darted forth its tongue, which advancing in a straight 

 hne, seldom failed of striking with its glutinous cupped ex- 

 tremity the object aimed at. But even when the point hap- 

 pened to err, the prey did not always escape, being, neverthe- 

 less, sometimes secured by a similar adhesive matter which 

 coated the sides. The tongue then retired, thus laden, into 



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