AUGUST. 205 



mal scales. The only sign of degeneracy is the central 

 cloudy mass of pigment, like a big cataract." 



I was naturally desirous of determining for myself 

 how far it was sensitive to light, but found the investiga- 

 tion beset with difficulties. Chloroformed lizards that 

 were deprived of their eyes, although the amputation was 

 dexterously performed, did not revive sufficiently to make 

 their subsequent movements suggestive; or did sympa- 

 thetic ophthalmia set in and affect the pineal eye ? 



I subsequently hit upon a plan, using very thin India- 

 rubber cloth, by which the eyes proper were effectually 

 closed, and the " eye " of the vertex left free. The lizards 

 thus provided with a blinding head-gear were separated 

 from their fellows and placed in a roomy inclosure, made 

 up of several almost dark and very light alternate sec- 

 tions, the temperature being even throughout the lizards' 

 range. The arrangement was, perhaps, too artificial for a 

 satisfactory series of observations, but it became evident 

 at once that the lizards recognized the difference between 

 the dark and light areas, and their prompt return to 

 the latter when removed from them, and again their ac- 

 tions when they returned, all showed the appreciation of 

 a difference, which I -know was not one of temperature, 

 but beyond this I could determine nothing ; but I recalled, 

 at this juncture, the significant . fact that in the woods 

 about May's Landing I noticed many lizards buried in the 

 fine sand and leaf-mold, their eyes closed and covered, 

 but the top of the head and a portion of the back for its 

 whole length exposed. The same was subsequently noted 

 as a position frequently assumed by the lizards in my 

 Wardian cases. If, therefore, the " pineal eye " is sensi- 

 tive to light, it is still of some use to the creature, as it 

 would certainly respond to a passing shadow, and so warn 

 the animal of the approach of a possible enemy. It cer- 

 tainly would be greatly to the lizard's advantage if it had 



