MAIL-CLAD ANIMALS. 



ii 



placed inside the ribs, instead of externally to them, as 

 in all other living animals. This type of armour, which 

 we may term box-armour, seems to have been a success, 

 since tortoises and turtles are, in certain parts of the 



FIG. 4. Upper surface of the carapace of a Tortoise. 



world, among the commonest of reptiles. In some of 

 those types which are dwellers in water, such as the 

 well-known soft tortoises, or mud terrapins, so abun- 

 dant in the Nile and other tropical and subtropical 

 rivers, the breast-plate and the back-plate of the 



