Page:Natural History, Reptiles.djvu/13

Rh Dragons, and the flying of the Pterodactyles, there is hardly any mode of animal progression which is not to be found among the Reptiles.” The temperature of the blood does not require that the body should be clothed with a substance, such as hair or feathers, which might resist the abstraction of animal heat. Hence the skin is either quite naked, as in the Amphibia, or covered with a sort of mail, composed of plates or scales, for defence.

It is in the warmer regions of the globe that Reptiles most abound; both as to the number of species, and of the individuals which constitute them. There also they display the greatest variety of form and colour, the most gigantic bulk, and the highest amount of animal energy. The few species that inhabit temperate and cold countries, commonly retire into concealment and become torpid on the approach of winter. Yet it has been remarked that they can more easily bear the rigour of a severe winter, than suffer the want of a hot summer. “It is interesting to remark the manner in which, according to Berghaus, the number of species diminishes as we pass from the sunny regions of the East to the duller and more cloudy climes of Western Europe. Thus Italy with her islands can number forty-seven species; France has thirty-one;