METACHROSIS. 225 



parent, urge the blood to rush more upon the skin, 

 and, according as the fluid fills itself or empties itself 

 of air, its colour becomes more or less lively.' By 

 the investigations of Mr. Houston (Trans, of Roy. 

 Irish Acad. xv. 177.) the proximate cause of change- 

 ability is connected with the circulatory system. The 

 skin of the changeable Saurians is not only very 

 thin, but highly vascular ; and he thinks that the 

 colour of the blood appearing through the semi- 

 transparent covering, and being variously modified by 

 its more permanent hues, is of itself sufficient to 

 account for every diversity of tint which the Chame- 

 leon can assume. He maintains the opinion that 

 these effects are produced by vascular turgescence, 

 'just as the increased redness in blushing is caused 

 by a rush of blood to the cheeks.' I would seek in 

 addition an illustration from the changeable hues in 

 the caruncles of the Turkey. There, too, aeration 

 produces a diversity of influences on the circulatory 

 system. The red blood distributed through these 

 parts increases and diminishes its intensity of tint 

 by the different aerations at the caprice of the bird, 

 and, being sometimes wholly deprived of its red 

 particles, flows colourless, as the fluids circulate in 

 the white of the eye." 



I have seen the Pearly-bellied Anolis only in 

 Westmoreland. In those parts of the coast of St. 

 EHzabeth which lie to the eastward of Black River, 

 and in the district around Spanish-town and Kings- 

 ton, it appears to be replaced by the Zebra Anolis, 

 {A. maculatus), a very handsome species, of rather 

 larger size, with fine contrasts of pale yellow and deep 



