260 COMMON CHAMELEON. 



in the living animal full half of their diameter : 

 they are covered with one single eyelid or skin, 

 pierced in the middle with a small hole of not 

 more than a line in diameter, through which the 

 pupil appears, surrounded by a gold-coloured iris: 

 the eyelid, or investing skin, is granulated like the 

 rest of the animal : the fore part of the eye is fast- 

 ened to the lid, so that the lid follows all the mo- 

 tions of the eye : sometimes one of the eyes will 

 move while the other is at rest, or turn forwards 

 while the other is directed backwards, or upwards, 

 while the other is turned downwards : by extend- 

 ing the skin of the orifice crossways the Chame- 

 leon can close its eyes, the hole then becoming a 

 longitudinal rima or slit : the optic nerves are 

 eight lines in length : the cornea is small ; the 

 sclerotica hard and thick ; but the hinder part 

 very thin : the choroides black under the iris, and 

 blueish at the bottom : the retina very thick, and 

 reddish : the humors all aqueous, the chrystalline 

 itself scarce distinct from the rest. 



The Brain is extremely small, scarce more than 

 a line in diameter, and not twice the thickness of 

 the spinal marrow, which is very white, the brain 

 itself being grey. 



The Heart is very small, not exceeding three 

 lines in length ; its point appearing truncated or 

 as if cut off: the auricles very large, especially the 

 left, and somewhat redder than the heart. 



The Lungs very large when inflated ; and di- 

 vided into several processes or saccular subdivi- 

 sions ; but when collapsed they appear small. 



