REP T I LI A 141 



consists of an upper portion, the carapace, and a lower 

 portion, the plastron. How are the other regions covered ? 

 What is the shape of the head ? Is the mouth at the 

 front, or on the under side ? Where are the nostrils ? 

 Are the motions of breathing visible ? Is there a beak or 

 snout ? Do the jaws contain teeth ? 



Do the eyes project? Which is thinner and more 

 movable, the upper or lower lid ? Identify the third eye- 

 lid {nictitating membrane). It is translucent and comes 

 from, and is drawn into, the inner corner of the eye. It 

 cleanses the eyeball. Frogs and birds have a similar 

 membrane. The circular ear drum is in a depression back 

 of the angle of the mouth. What other animal studied 

 has an external ear drum ? 



The tortoise has a longer, more flexible neck than any 

 other reptile. Why does it have the greatest need for 

 such a neck ? Is the skin over the neck tight or loose ? 

 Why ? 



Do the legs have the three joints or parts found on the 

 limbs of most vertebrates ? How is the skin of the legs 

 covered? Do the toes have claws? Compare the front 

 and hind feet. Does the tortoise slide its body or lift it 

 when walking on hard ground ? Lay the animal on its 

 back on a chair or table at one side of the room in view 

 of the class. Watch its attempts to right itself. Are 

 the motions suited to accomplish the object ? Does the 

 tortoise succeed ? 



What are the prevailing colors of turtles ? How does 

 their coloration correspond to their surroundings ? 



What parts of the tortoise extend at times beyond the 

 shell ? Are any of these parts visible when the shell is 

 closed? What movements of the shell take place as it is 

 closed ? Is the carapace rigid throughout ? Is the plastron ? 



