allude to the lizard with a frill round its neck, which has been universally likened to that worn by Queen Elizabeth:  it is called the frilled agama.  It is supposed that this harmless sauroid extends this frill to frighten away its enemies; as old ladies, who can preserve their presence of mind in the neighbourhood of a bull, open their umbrella to frighten it into an opposite direction.  Under these interesting sub-families are grouped the varieties of a species of agama that has won for itself an imperishable reputation—­having furnished imaginative minds with matter for the most extravagant speculations—­and yielded to the political writer abundant sarcastic images.  No politician who has thought proper in the course of a long career, to change his old principles for new ones (as housewives exchange worn-out apparel for new gilded pottery); no philosopher who has by turns embraced conflicting principles of human action; no man of science who has published two opposite theories of the formation of our universe, can pause without emotion before this case of classed Chameleons; for the politician, the philosopher, and the man of science have inevitably figured in hostile reviews under the head of colour-changing sauroids.  The popular notion respecting the colour-changing powers of these lizards is, that at will the chameleon can habit itself in any colour of the rainbow; that by turns it is a red chameleon, a blue chameleon, a green chameleon, and a yellow chameleon.  The fact of the case is very far-from this notion.  Chameleons are found chiefly in Africa and India, but also in some of the tropical islands.  In their habits they are sluggards, lounging generally about trees, and distending their long tongues covered with a glutinous secretion, to secure passing insects, upon which they subsist.  They have eyes of wonderful power, and can look backwards and forwards at the same moment; but as regards their colour, it is well to assure the visitor, that their usual tint when resting in the shade is a blue-grey, which sometimes pales to a lighter grey, turns green, assumes a brown-grey tint, or darkens to a decided brown.  These are the sober observations of observant naturalists on the subject.

The class of reptiles to which the visitor should next direct his attention are those classed by Cuvier and others under the head of Ophidia, or

Serpents.

The particulars in which, the serpent differs from the lizard are, that the former have no feet, cast their bright coats annually (like our metropolitan postmen), and swallow their food without masticating it.  They occupy seven cases.  The upper part of the first case contains many of the most poisonous serpents.  Among these are the well-known and formidable Rattlesnakes of America, with specimens of their rattles lying near them, which, as the visitor-will see, are a succession of osseous joints.  Here too are the terrible cobra di capello, and other poisonous