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The Contemporary Review, Volume 36, September 1879

Our English lizards are true lizards


All

the foregoing birds have a multitude of points in common; indeed, so close is the similarity of their structure that their subdivision into orders is a matter of much difficulty and dispute. They are collectively spoken of as the _Carinatae_, from the keeled form of their breast-bone.

Widely apart from them stands another group made up almost entirely of large birds, which agree not only in having no power of flight, but also in certain significant structural characters, amongst which may be mentioned the absence of a keel on the breast-bone.

This latter group is sometimes spoken of as the order _Struthiones_ from the ostrich (_Struthio_), which is its typical form. Sometimes these keelless birds are called _Ratitae_. Besides the ostrich, the rhea, cassowary, and emeu are included within the group; also the small and nocturnal _Apteryx_ of New Zealand and those giants of featherdom, the huge species of dinornis, all also of New Zealand and all now extinct.

With this our list of birds might close, but for a bird which anciently existed in Europe so strangely different from all modern kinds, that it must certainly be here adverted to. This bird is the _Archeopteryx_, found in fossil in the Solenhofen States.

The class Aves, like the class Mammalia, consists of animals with hot blood, but all birds have feathers and a number of other peculiarities

of structure, as will appear later.

The next class to be adverted to is the class which includes all reptiles properly so-called--the class _Reptilia_.

The reptiles which exist in the world to-day may be classed in four well-marked sets, each of which has the value of an "order"--(1) crocodiles, (2) lizards, (3) serpents, and (4) tortoises. The names of these creatures alone suffice to indicate the fact that the class of reptiles presents us with an extraordinary amount of diversity of form as compared with the class of birds with which, nevertheless, reptiles have, as we shall hereafter see, very close relations. Indeed, in the diversity of kinds which it contains, the class _Reptilia_ at the least fully equals the class Mammalia, especially if the extinct kinds are taken into consideration. The number of species of reptiles, both living and extinct, much exceeds also the number of living and extinct mammals.

To begin once more with forms which are the least strange and unknown, we may start with the little elegant and harmless lizards of our heaths and commons, which will serve as types of the order to which they belong--the order _Lacertilia_. That order is an extremely numerous one, containing many families, differing much in form. Our English lizards are true lizards, belonging to the typical genus _Lacerta_ and to the typical family _Lacertidae_. The rather well-known large American lizard, _Iguana_, is the type of another and very extensive family (almost entirely confined to America), while a nearly-allied family (_Agamidae_) is an Old World group. Amongst the curious forms found in the latter family may be mentioned the frilled and moloch lizards of Australia, and those little harmless lizards of India which go by the formidable name of "flying dragons" (_Draco_). They are the only existing aerial reptiles--not that they can truly "fly" at all, but they are enabled to take prolonged jumps, and to sustain themselves to a considerable extent in the air by means of the extremely distensible skin of their flanks which, when extended, is supported by a peculiar solid framework hereafter to be described. Some of the largest lizards are called "monitors," and are common in Egypt; they belong to the family _Monitoridae_.


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