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habit, and the overlapping horny plates covering the carapace 

 are the source of "tortoise-shell". 



(3) The Side-necked Tortoises are a rather remarkable as- 

 semblage of fresh-water form, owing their name to the fact that 



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the head and neck cannot be drawn straight back into the 

 hollow of the shell, but the same end is effected by bending back 

 the head sideways. These tortoises are all restricted to the 

 southern land-masses, and range right round the globe, being 

 represented in South America, Africa, Madagascar, Australia, 

 and New Guinea. 



(4) Soft Tortoises. — These are found in the rivers of the 



