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 CHAPTER XII

REPTILIA (REPTILES)

This class is divided into four orders which have such marked differences of external form that there is no difficulty in distinguishing them. These orders are represented by Lizards, Snakes, Turtles, and Alligators. Of these, only the forms of lizards and alligators have similar proportions, but there is a marked difference in their size, lizards being, in general, the smallest, and alligators the largest of the reptiles.

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