TURTLE TRAITS 129 



to them as do any living creatures, and when we 

 see a huge snapping turtle come out of the water 

 and walk about on land, we cannot fail to be 

 reminded of the fellow with the armoured back. 



Turtles are found on the sea and ou land, the 

 marine forms more properly deserving the name 

 of turtles ; tortoises being those living on land or 

 in fresh water. We shall use the name turtle as 

 significant of the whole group. The most natural 

 method of classifying these creatures is by the 

 ;way the head and neck are drawn back under the 

 shell; whether the head is turned to one side, or 

 drawn straight back, bending the neck into the 

 letter S shape. 



The skull of a turtle is massive, and some have 

 thick, false roofs on top of the usual brain box. 



The "house" or shell of a turtle is made up of 

 separate pieces of bone, a central row along the 

 back and others arranged around on both sides. 

 These are really pieces of the skin of the back 

 changed to bone. Our ribs are directly under the 

 skin of the back, and if this skin should harden 

 into a bone-like substance, the ribs would lie flat 

 against it, and this is the case with the ribs of 

 turtles. So when we marvel that the ribs of a 

 turtle are on the outside of its body, a second 

 thought will show us that this is just as true of 

 us as it is of these reptiles. 



This hardening of the skin has brought about 

 some interesting changes in the body of the turtle. 



