GENERAL CHARACTERISTICS 2365 



Reptiles. This discrepancy may, no doubt, be partly explained by the very early 

 period at which certain groups of the class, such as crocodiles and tortoises, spread 

 themselves over the surface of the globe. As regards the dispersive powers of Rep- 

 tiles in general, these according to Dr. Giinther, are but limited. All these crea- 

 tures, he writes, " are much specialized in their mode of life and propagation, and 

 ill-adapted to accommodate themselves to a change of external condition. As air- 

 breathing, cold-blooded animals they are unable to withstand prolonged cold; they 

 are therefore entirely absent in the Arctic and Antarctic zones; and such as escape 

 the effects of the winter months in temperate zones by passing them in a torpid con- 

 dition in well-sheltered places are not peculiarly organized forms, but offshoots 

 from those inhabiting warmer climes. The tropical and subtropical zones are the 

 real homes of the reptilian type, which there has reached its greatest development 

 as regards size and variety of forms. In the north, Chelonians advance only to 50 

 latitude in the Western and to 56 in the Eastern Hemisphere; lizards to about 56 

 in British Columbia, and close to the Arctic Circle in Europe; while snakes disap- 

 pear some degrees before the lizards. Also in the south, lizards extend into higher 

 latitudes than snakes, namely, to the straits of Magellan, while the latter do not 

 seem to have advanced beyond 40 south latitude, and Chelonians to 36." 



Of the various zoological regions into which the globe has been divided, the 

 Oriental or Indian region, according to the same observer, is characterized by the 

 number of fresh-water soft tortoises* and S-necked tortoises,* land tortoises being 

 scarce. Crocodiles, inclusive of the characteristic long-necked garials, are numer- 

 ous, as are lizards and snakes especially pythons. Africa has comparatively 

 few Reptiles, although characterized by its numerous land tortoises, soft tor- 

 toises, and side-necked tortoises,* the crocodiles being represented only by members 

 of the typical genus; while lizards and snakes are comparatively numerous. Among 

 the lizards, monitors, and among the snakes, pythons, are common to the Oriental 

 and African regions; while half of the exclusively Old- World group of chameleons 

 are African. Madagascar is even more remarkable for the number of its 

 chameleons; its land and side-necked tortoises are numerous, although soft 

 tortoises, as in South America, are absent; there is one crocodile; and among the 

 lizards the South- American group of iguanas is abundant; while the snakes, among 

 which none is poisonous, are also of a South- American type. In the warmer parts 

 of the Euro- Asiatic region (exclusive of India, etc. ) the reptile fauna is mainly a 

 mixture of Oriental and African types, although there are some peculiar forms. 

 The only non- American alligator inhabits Central China. In the Australian or 

 tropical Pacific region, exclusive of New Zealand, we meet with one group of laud 

 tortoises, side-necked tortoises, and a crocodile; while among the lizards there are 

 skinks, geckos, monitors, and the so-called agamoids; the latter occurring in all the 

 regions above mentioned, except Madagascar. Venomous snakes here outnumber 

 the harmless ones. The Tropical and South- American region is characterized by 

 the presence of land and side-necked tortoises, to the exclusion of soft tortoises. 

 Crocodiles and caimans are numerous (the latter being characteristic); while of the 



*For the explanation of these and other names, the reader must refer to later chapters. 



