=Comparison of Lizards and Salamanders.=--To make clear the difference between reptiles and batrachians, it will be well to compare the orders in the two classes which resemble each other in size and shape; namely, lizards and salamanders (Figs. 263 and 264). State in a tabular form their differences in _skin, toe, manner of breathing, development from egg, shape of tail, habitat, habits_. Each has an elongated body, two pairs of limbs, and a long tail, yet they are easily distinguished. Are the differences suggested above valid for the other batrachians (frogs) and other reptiles (_e.g._ turtles)? Trace the same differences between the toad or frog (Fig. 250) and the “horned toad,” which is a lizard (Fig. 265). [Illustration: FIG. 265.--“HORNED TOAD” LIZARD, of the Southwest (_Phrynosoma cornita_). × ²⁄₃.] STUDY OF A TURTLE OR TORTOISE SUGGESTIONS.--Because of the ease with which a tortoise or turtle may be caught and their movements and habits studied, it is suggested that one of these be studied as an example of reptiles. Besides a live specimen, a skeleton of one species and the shells of several species should be available. [Illustration: FIG. 266.--EUROPEAN POND TURTLE (_Emys lutaria_). (After Brehms.)] The =body (of a turtle or tortoise) is divided= distinctly into _regions_ (Fig. 266). Is there a head? Neck? Trunk? Tail? The trunk is inclosed by the _so-called shell_, which 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 eyelid (_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?