etimes asleep whilst the other is vigilant and active; one will
assume a green tinge whilst the opposite one is red; and it is said that
the chameleon is utterly unable to swim, from the incapacity of the
muscles of the two sides to act in concert.

_Ceratophora_.--This which till lately was an unique lizard, known by
only two specimens, one in the British Museum, and another in that of
Leyden, was ascertained by Dr. Kelaart, about five years ago, to be a
native of the higher Kandyan hills, where it is sometimes seen in the
older trees in pursuit of insect larvae. The first specimen brought to
Europe was called _Ceratophora Stoddartii_, after the name of its
finder; and the recent discovery of several others in the National
Collection has enabled me, by the aid of Dr. A. Guenther, to add some
important facts to their history.

This lizard is remarkable for having no external ear; and it has
acquired its generic name from the curious horn-like process on the
extremity of the nose. This horn, as it is found in mature males of ten
inches in length, is five lines long, conical, pointed, and slightly
curved; a miniature form of the formidable weapon, from which the
_Rhinoceros_ takes its name. But the comparison does not hold good
either from an anatomical or a physiological point of view. For, whilst
the horn of the rhinoceros is merely a dermal production, a
conglomeration of hairs cemented into one dense mass as hard as bone,
and answering the purpose of a defensive weapon, besides being used for
digging up the roots on which the animal lives; the horn of the
_ceratophora_ is formed of a soft, spongy substance, coated by the
rostral shield, which is produced into a kind of sheath. Although
flexible, it always remains erect, owing to the elasticity of its
substance. Not having access to a living specimen, which would afford
the opportunity of testing conjecture, we are left to infer from the
internal structure of this horn, that it is an erectile organ which, in
moments of irritation, will swell like the comb of a cock. This opinion
as to its physiological nature is confirmed by the remarkable
circumstance that, like the rudimentary comb of the hen and young cocks,
the female and the immature males of the _ceratophora_ have the horn
exceedingly small. In mature females of eight inches in length (and the
females appear always to be smaller than the males), the horn is only
one half or one line long; while in immature males