AMPHIBIANS 



2629 



to limit their habitat. When they occur on islands, it is probable either that their 

 eggs have been carried by birds, or that there has been a comparatively recent sep- 

 aration from the mainland. In absolutely desert districts Amphibians are unknown; 

 while in countries where there is a long dry season, followed by a period of rains, 

 they are in the habit of becoming torpid during the former; the length of the sleep 

 in one Javan species being upward of five months. In cold climates all the members 

 of the class become torpid during the winter. As regards their general distribution, 

 Amphibians closely resemble fresh-water fish, and. differ widely from lizards. In- 

 deed, from an Amphibian point of view, the globe may be divided into two great 

 regions, namely, a northern one characterized by the abundance of newts and sala- 



MOOR FROGS. 



(Natural size.) 



manders, and the absence of csecilians; and a southern one distinguished by th* 

 want of the former and the presence of the latter group. 



Habits In their mode of life, it is probable that very few Amphibians are 



diurnal; most of the terrestrial forms making their appearance abroad 

 with the first shades of evening, and retiring to their hiding places at dawn. In 

 wet or cloudy weather frogs and toads especially in South America frequently 

 appear in great numbers during the day; and both these groups are in the habit of 

 making night hideous with their croakings. Although in all cases the sdults are 

 carnivorous, the larvae subsist more or less exclusively on vegetable substances; 

 some confining themselves to that kind of diet, while others also consume animal- 

 cules and other minute creatures. 



