194 REPTILES AND BATRACHIANS 



inside out in the process. On account of the great 

 absorbing powers of the skin, which is more or less 

 comparable to a sponge, most Batrachians frequent damp 

 localities ; in the few cases in which they inhabit dry, arid 

 districts they spend the greater part of their existence 

 underground, emerging only at night, or during the rainy 

 season. The majority of Batrachians are born in water, 

 in which they spend their infancy in a larval, fish-like state, 

 breathing by gills. Although some will breed several times 

 in a year, the greater number, especially those inhabiting 

 temperate regions, do so only once, the time of repro- 

 duction varying considerably according to the different 

 species. Take, for example, the three British species of 

 the Anura ; the Common Frog, Rana temporaria, breeds 

 towards the end of February or the beginning of March, 

 the Common Toad, Bufo vulgaris, at the end of March 

 or the beginning of April, and the Natterjack Toad, Bufo 

 calamita, from the end of April to the beginning of July. 



In many cases the males precede the females to the 

 water, while in others the female is secured on the journey 

 to the pond resorted to for breeding. The males of many 

 tailed Batrachians, most newts, for instance, are dis- 

 tinguished, during the breeding season, by ornamental 

 appendages, such as crests, or by more vivid colours. The 

 eggs, which are spherical bodies surrounded by a trans- 

 parent gelatinous envelope, are either laid singly, each 

 fixed to submerged bodies, or in strings or bands, in which 

 case they are twined round plants ; or they may form large 

 masses, which, in a few, such as those of the Common 

 Frog, Rana temporaria, float on the surface. 



The amount of protection which the gelatinous envelope 



