40 VERTEBRATA. REPTILIA. 



once in three or four days, and would not eat hard- 

 shelled beetles. They generally slept on the top of 

 the basket, their heads projecting over the edge, and 

 their tails curled round one of the small divisions of 

 the wicker-work, and it was curious to observe the 

 firmness of their hold in this way. On going in 

 with a candle, they always appeared of a pale ashy 

 stone colour, or a spectral blue, like the tint cast 

 upon the face, by coining opposite a blue bottle in a 

 chemist's window. Their motions were exceedingly 

 slow, always firmly attaching one foot before letting 

 go with the other. They were lost several times, 

 and Mr. S. was afraid to step about the room, lest 

 he should tread on them, but they were generally 

 found in the folds of the curtains, not on the blue 

 lining, but on the chintz. One side was often seen 

 nearly of a stone colour, while the other was black- 

 ish green : the changes of hue were always rapid, 

 and attended by either elevation or depression of the 

 ribs. Mr. S. adds, "the skin of the creatures I 

 should liken to an infinite number of facets of a 

 certain determinate figure, and I think the changes 

 of colour depended on the power of the animals to 

 elevate, alter, and depress the faces or angles of 

 these facets, and the consequent difference of angle at 

 which the light was received."* This theory is cer- 

 tainly ingenious, and might easily be confirmed, if 

 correct, by microscopical examination. 



* London's Mas. N. H. iii. 232. 



