The _Batrachians_, again, are the only exception to another great characteristic of the reptile class, the hard, dry covering of plates or scales. The reptiles all produce their young from eggs, or are "oviparous"--some hatch their eggs within the body, and produce their young alive, or are "ovo-viviparous." These are the characters belonging to all members of the reptile-class. The class is subdivided into orders somewhat thus: 1. The _Testudinate_ (tortoises and turtles). 2. _Enaliosaurian_ (all fossil, the _Ichthyosaurus_ and his like). 3. _Loricate_ (crocodiles and alligators). 4. _Saurian_ (lizards). 5. _Ophidian_ (serpents); and the last order, _Batrachian_ (frogs, toads, &c.); which is, by some, parted from the reptiles, and established as another class. Now we have in England no tortoises or turtles, and no crocodiles: and the fossil order is, in all places, extinct; so our reptiles can belong only to the three last-named orders, Lizards, Serpents, and Batrachians. Thus we come back, then, to our Lizards, of which we have among us but two genera, a single species of each. These are the Common Lizard, well known to us all, and the Sand Lizard, known only to some of us who happen to live upon the southern coast. The species of lizard so extremely common in this country, has not been found in countries farther south, and is, in fact, peculiar to our latitude. We, therefore, may love him as a sympathetic friend. The sand lizard (_Lacerta agilis_) is found as far north as the country of Linnæus, and as far south as the northern part of France; in England, however, it seems to be rare, and has been detected only in Dorsetshire--chiefly near Poole, or in some other southern counties. It frequents sandy heaths, and is of a brown sandy color, marked and dotted; but there is a green variety said to be found among the verdure of marshy places. It is larger than our common lizard, averaging seven inches long, is very timid, and when made a prisoner pines and dies. Its female lays eggs, like a turtle, in the sand, covers them over, and leaves them to be hatched by the summer sun. This kind of lizard, therefore, is oviparous. The eggs of our common lizard are hatched also by the sun; for, reptiles having no heat of their own, can not provide that which is necessary to the development of an embryo; but in this case the sun hatches them within the parent's body. The female of this lizard stretches herself out upon a sunny bank, and lets the bright rays fall upon her body while she lies inactive. At this period, she will not move for any thing less than a real cause of alarm. She is not sunning herself lazily, however, but fulfilling an ordinance of God. The eggs break as the young lizards--three to six--are born. This lizard is, therefore, ovo-viviparous. The little ones begin at once to run about, and soon dart after insects, their proper food; but they accompany the mother with some instinct of affection for a little time.