The power possessed by these creatures of changing colour has been a subject of wonder and exaggeration from an early period. Wood, in his ‘Zeograplly,' gives the following translation of the account given by the French academicians of this phenomenon : "The colour of all the eminences of our chameleon, when it was at rest, in the shade, and had continued a long time undisturbed, WWI a bluish gray, except under the feet, where it was white inclining to yellow ; and the intervals of the granules of the skin were of a pale and yellowish-red. This gray, which coloured all the parts exposed to the light, changed when in the sun; and all the places of its body which were illuminated, instead of their bluish colour, became of a were tinged, and of a bright red, which is the colour of the bottom of the skin which is visible between the granules; the rest of the skin not enlightened by the sun, and which was of a paler gray thau ordi nary, resembled a cloth made of mixed wool ; some of the granules being greenish, others of a minhne gray, and others of the usual bluish-gray, the ground remaining as before. When the sun did not shine, the first gray appeared again by little and little, and spread itself all over the body, except under the feet, which continued of the same colour, but a little browner ; and when, being in this state, some of the com pany handled it, there immediately appeared on its shoulders and fore legs several very blackish spots, about the size of a finger nail, and which did not take place when it was handled by those who usually took care of it. Sometimes it was marked with brown spots, which inclined towards green. We afterwards wrapped it up in a linen cloth, where having been two or three minutes we took it out whitish ; but not so white as that of %Well Aldrovandus speaks, which was not to be distinguished from the linen on which it was laid. Ours, which had only changed its ordinary gray into a pale one, after having kept this colour some time, lost it insensibly. This experiment made us question the truth of the chameleon's taking all colours but white, as Theophrastus and Plutarch report, for ours seemed to have such a disposition to retain this colour, that it grew pale every night, and when dead it had more white than any other colour ; nor did we find that it changed colour all over the body, as Ariatotle reports; for when it takes other colours than gray, and disguises itself to appear in masquerade, as slilian pleasantly says, it covers only certain parts of the body with them. Lastly, to conclude the experiments relative to the colours which the chameleon can take, it was laid on substances of various colours, and wrapped up therein ; but it took not them as it bad done the white, and it took that only the first time the experi ment was made, though it was repeated several times on different days. In making these experiments we observed that there were a great many places of its skin which grew brown, but very little at a time : to be certain of whieh we marked with small specks of ink those granules which to us appeared whiteat in its pale state, and we always found that when it grew brownest and its skin spotted, those grains which we had marked were always less brown than the rest." Numerous theories, some of them sufficiently absurd, have been proposed to account for this phenomenon. It was reserved for Milne-Edwards to give a complete and satisfactory explanation.
In a paper published in the Annales des Sciences Naturelles ' for January, 1834, and translated in the lith vol. of the Edinburgh Now Philosophical Journal,' he has given the result of his investi gations. The following are his conclusions :— 1. That the change in the colour of Chameleons does not depend essentially either on the more or leas considerable swelling of their bodies, or the changes which might hence result to the coudition of their blood or circulation; nor does it depend on the greater or less distance which may exist between the several cutaneous tubercles; although it is not to be denied that these circumstances probably exercise some influence upon the phenomenon.
2. That there exists in the skin of these animals two layers of membranous pigment placed the one above the other, but diposed in such a way as to appear simultaneously under the cuticle, and some times in such a manner that the one may bide the other.
3. That everything remarkable in the changes of colour that manifest themselves in the Chameleon may be explained by the appearance of the pigment of the deeper layer, to an extent more or less considerable, in the midst of the pigment of the superficial layer; or from its disappearance beneath this layer.
4. That these displacements of the deeper pigment do in reality occur ; and it is a probable consequence that the chameleon's colour changes during life, and may continue to change even after death.
5. That there exits a close analogy between the mechanism by the help of which the changes of colour appear to take place in these reptiles, and that which determines the successive appearance and disappearance of coloured spots in the mantles of several of the Cephalopods.
This family embrace but the one genus, Chameeleo. Dr. J. E. Gray places the Chanicrlsonidm in the tribe Dendrosaura, of the sub order Pachyglosser, of the order Saura, or Lizards. The tribe Dendro saura embrace only this family, and have the following characters : Scales of the belly, sides, and back, granular. Tongue elongate, sub-cylindrical, worm-like, very extensile. Eyes globular, very mobile, with a small central round opening. Toes equal, united in two opposing groups.
The species are inhabitants of the Old World, in Africa and Asia, and are naturalised in Southern Europe.
The following species are described in the Catalogue of the Specimens of Lizards in the British Museum : • Back with an erect fin. Belly crested.
C. crie at us, the Fringed Chameleon. A native of Fernando Po. •• Back high, compressed. Belly and sidee with a toothed crest.
C. lateralis, the Side-Crested Chameleon. It is a native of Madagascar.
"• Back and belly with a toothed crest. Sides simple.
+ Scales equal, small. Muzzle simple.
C. rulgaris, the Chameleon. It is the C. mutabilis, Meyer ; C. cinereus, Aldrovandus ; C. Parisiensis, C. Zcylandicus, and C. Mexi canal, Laurent ; C. carinatus, C. subcrocems, C. calcaratus, Merrem ; C. Zebra, Bory; Lacerta Chameleon, Linnaeus. It is a native of the East Indies, and the species which is most frequently brought to England.
Back and belly not crested.
C. Parsonii, Parson's Chameleon. A native of Madagascar.
C. Owenii, the Three-Horned Chameleon. It is a native of Fer nando Po.
C. Brookesianus, Brookes's Chameleon. Locality unknown. Named from a specimen in the Museum of Joshua Brookes.