Change of Colour in Lizards. 58 1 



which I have since seen in other lands, I have no doubt what- 

 ever of their origin. In the generality of cases, perhaps, 

 these lights proceed from orthopterous ? or other insects at- 

 tached to swampy grounds, and luminous only during the 

 season of their nuptials. 



Lumiiiortsness of the Sea. (I. 156.) — The most satisfactory 

 information on the luminousness of the sea, and the animals 

 producing these lovely sparks, will be found m one of the 

 numbers of Thomson's Zoological Researches [see IV. 256.], 

 a work, of course, in the hands of all naturalists. While sailing 

 in the more shallow parts of the Caribbean Sea, and looking 

 over the vessel's side when becalmed in these dangerous waters, 

 in the midst of reefs, I have seen at the bottom huge molluscous 

 or radiate animals emitting the splendour of a lamp, but could 

 never ascertain the species. 



Putrescent matter is occasionally highly luminous in the 

 West Indies. [Mr. Guilding has a note, in another part, upon 

 the remarks of some correspondents given in II. 209. — The 

 gelatinous mass containing portions of the frog was probably 

 vomited by the heron. I have known similar matter in the 

 West Indies to become highly phosphorescent.] 



It has been already observed that the larvae of some insects 

 emit light. The larva of an E'later ? as far as I can determine, 

 was lately sent to me, which was said, by the respectable 

 person from whom I obtained it, to have been very luminous 

 between every segment of the abdomen. 



The Voluntary Changing of Colour i?i Several Genera of 

 Lizards^ and more especially in QhamcBleon and Anblis. (1. 157.) 

 — There is not in nature a more singular phenomenon than this. 

 The mode of effecting this miraculous change does not seem 

 to have been yet fully determined. It may depend upon some 

 small, peculiar, and supplementary system of vessels pouring 

 a coloured fluid to the integuments, or withdrawing it from 

 the skin; or it may proceed from the more simple action of 

 the arterial system, from the rapidity or lethargy of the cir- 

 culation : though one would suppose a temporary stagnation 

 would deprive the creature of all activity. It is strange that 

 the power is within the perfect control of the lizard, and is not 

 abandoned even at the eager moment of springing on the prey. 



The passions of the human mind do indeed change the 

 colour of the face, and distort the countenance ; but these 

 changes indicative of strong feeling are transitory, if not mo- 

 mentary, and almost in all cases involuntary : whereas the 

 lizards can regulate this protean power for hours, days, or 

 months. By inflating the body, the numerous scales might be 

 separated to certain degrees, and thus affect the general colon r- 



pp 3 



