534 Observations on the Chameleon. 



standing the strictly symmetrical structure of the chameleon, 

 as to its two lateral halves, the eyes move independently of 

 each other, and convey different impressions to their respec- 

 tive centres of perception. The consequence is, that when 

 the animal is agitated, its movements appear like those of 

 two animals glued together. Each half wishes to move its 

 own way, and there is no symmetry of action. The result 

 not being in the direction of the diagonal determined by the 

 parellellogram of simultaneous or well-regulated forces, is sel- 

 dom in harmony with what, in the opinion of the observer, 

 the whole animal ought to do. The chameleon is therefore 

 not able to swim, like other animals ; it is so frightened if put 

 into water, that the faculty of concentration is lost, and it 

 tumbles about as if in a state of intoxication. On the other 

 hand, when the creature is undisturbed, the eye which re- 

 ceives the strongest impression propagates it to the common 

 centre, and prevails upon the other eye to follow that impres- 

 sion, and direct itself towards the same object; and if this 

 object be prey of any kind, the mesial line of the head is 

 moved in the direction of it, whereupon the two visual rays 

 form the angle into the vertex of which the butt-end of the 

 tongue is projected like a bolt. 



The chameleon, moreover, may be asleep on one side and 

 awake on the other. When cautiously approaching my spe- 

 cimen at night, with a candle, so as not to awaken the whole 

 animal by the shaking of the room, the eye turned towards 

 the flame would open, and begin to move, and the correspond- 

 ing side to change its colour ; whereas the other side would 

 remain for several seconds longer in its torpid and unchange- 

 able state, with its eye shut. 



In short, I could never look at my chameleon without sup- 

 posing it to look like twins adhering longitudinally to each 

 other, the more so, as the linea alba is like a strong suture ; 

 the palate longitudinally cleft ; and the toes in the hind feet 

 inversely divided as to those of the fore feet. In the latter, 

 two toes belong to the external, and three to the internal di- 

 vision ; whereas in the hind feet the respective numbers are 

 inverted : and I am inclined to think that the anatomy of the 

 embryo of the chameleon would lead to interesting results in 

 this respect.* 



I ought to remark that I have several times felt what I 



* I had no opportunity of dissecting the chameleon, having only the loan 

 of my specimen during its life, on a promise that I would send the carcass 

 to the Museum of Schneppenthal. I have only dissected and prepared the 

 tongue and its appendages. 



