Pickerel frog (R. palustris), light brown with two rows of large, oblong, square blotches of dark brown on the back, a brown spot above each eye, and a dark line from the nostril to the eye; upper jaw white and black. Habitat, eastern United States among mountains.
Wood frog (R. sylvatica), pale reddish brown; a black band across the pointed face. This smallest of our species is to be found only in damp woods, resorting to water only in early spring to deposit its eggs; and it is almost silent.
Green, or spring frog (R. clamatans), green or bronze-brown, brighter in front, with more or less small black spots; yellowish white below. This is a rather solitary frog, living in springs and small ponds, where it utters the familiar "chung" at frequent intervals. It is distinguished by the enormous size of its eardrum.
Bullfrog (R. catesbiana), greenish, brightest on the head, and with small dark spots on its back; legs blotched; eardrum large; toes broadly webbed. Length five to eight inches, breadth four to five inches. It utters a roar not unlike that of a distant bull, and a company of them on a still summer evening will awaken the neighborhood. Bullfrogs are present throughout the eastern United States and Canada, west to the dry plains; and furnish the market with "saddles" (their hind legs) as a table delicacy when fried. These frogs may lay 12,000 eggs apiece.
All our frogs lay their eggs in water in rounded masses, not in strings, as do the toads, usually attached to some submerged stick or plant stem. The tadpoles, light in color, are very voracious, and feed on every sort of flesh that they can bite off and chew with their horny jaws. On the approach of winter the frogs—except the wood frog, which hibernates in the loam of the forest, or in some rotten stump—sink into the mud of the pond or marsh where they live, and pass the cold months in torpidity. Their food is almost exclusively insects, caught by the tongue, but the big bullfrogs seize with their mouths any small creature that comes their way.
[CHAPTER XX]
REPTILES—MONARCHS OF THE MESOZOIC WORLD
What is a reptile? It is a cold-blooded, air-breathing vertebrate, with one occipital condyle, complete right and left aortic arches, red blood and a covering of scales. The classification of the class (Reptilia) recognizes the existence of many distinct subdivisions, as follows:
Proreptilia (extinct).