CHAPTER III 



DISTRIBUTION AND HABITS 



Amphibia usually associated with stagnant fresh water. Geographical dis- 

 tribution. Notogaea and Arctogaea. Oceanic and other islands. Food and feed- 

 ing. Relations to salt and moisture. ^Estivation and hibernation. 



AS we have mentioned above, Amphibia live only on land 

 or in fresh water, and usually they are confined to the 

 neighbourhood not merely of fresh water, but to that 

 of stagnant or slowly moving fresh water. This is particularly 

 true of the great majority of species whose eggs are laid or whose 

 larvae are developed in the water. They live therefore either in 

 or near swamps, marshes, ditches, ponds, sluggish streams or 

 lakes; but there are numerous exceptions which are either 

 viviparous or carry the eggs on their bodies, the young passing 

 through the whole of their development without entering the 

 water. A few species of Anura, e.g. Chiroleptes platycephalus, 

 live in the arid regions of Central Australia ; they are able to 

 survive by living underground in burrows and by storing up 

 quantities of water in their bodies. Some Anura are almost 

 entirely aquatic in their habits, as Xenopus and Pipa, others 

 enter the water chiefly in the breeding season, but the most in- 

 teresting adaptations are those related to arboreal life. Tree- 

 frogs occur in all the forest regions of the world, and are not all 

 of one division of the Order, but occur in all the chief divisions : 

 the Hylidae among the Arcifera are one of the largest groups 

 of tree-frogs, but among the Ranidae the Dendrobatinae in S. 

 America have similar habits, and most of the species of Hy lodes 

 among the Cystignathidae are arboreal. Salamandra atra is an 

 Alpine species extending to altitudes of 9000 feet in the Euro- 

 pean Alps ; its young are born fully developed but it neverthe- 

 less lives in damp and shady places. Proteus anguinus and 

 Typhlomolge rathbuni are subterranean, the former living in the 

 streams of the limestone caves of Dalmatia, the latter in Texas. 



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