CHAPTEE YII 

 skin, smell, hearing, eyes, digestive tract 



Skin Shedding 



The skin of amphibians is slied frequently — some- 

 times at regular intervals ; but the frequency depends 

 upon many conditions of growth, health, etc. In the 

 frog-forms some shed it once a week with great regu- 

 larity, at certain seasons in summer. Again this may 

 become quite irregular. In these, the skin tends to 

 come off all in one piece, but there are instances 

 where it is torn off in strips. Toads appear to get 

 rather excited at this disrobing, and while the process 

 may be usually easy there are times wdien the skin 

 comes with great difficulty. They seem to call upon 

 that internal reservoir of water to moisten the dried 

 skin occasionally ; and whether it come in strips 

 or as a seamless whole, they invariably swallow it 

 — sometimes rolling the mass into a ball with the 

 hands. 



The dry-land forms are said to shed their skins in 

 strips, and these too are eaten at once. We should 

 remember that this is not really the skin proper that 

 is shed, but a thin, membranous — almost horny — out- 

 side covering called the epidennis. In all creatures 

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