. The dinosaur book : the ruling reptiles and their relatives. Dinosaurs; Reptiles, Fossil. The frogs and toads have become highly modified. The head is large, the neck and body short. The elongated hind legs serve as efficient springs to propel the animal in long leaps, while the short forelegs are firmly attached to the body and strength- ened, to take up the shock of landing. The tail, so typical of most vertebrates, has been lost. All in all these melodious friends of the swamp and stream are highlv successful animals. They had their beginnings in Triassic times, and from the Jurassic to t
. The dinosaur book : the ruling reptiles and their relatives. Dinosaurs; Reptiles, Fossil. The frogs and toads have become highly modified. The head is large, the neck and body short. The elongated hind legs serve as efficient springs to propel the animal in long leaps, while the short forelegs are firmly attached to the body and strength- ened, to take up the shock of landing. The tail, so typical of most vertebrates, has been lost. All in all these melodious friends of the swamp and stream are highlv successful animals. They had their beginnings in Triassic times, and from the Jurassic to the Recent period they have persisted in es- sentially their present highly modified condition. The salamanders are seemingly rather An extraordinary skull shaped somewhat like a broad arrowhead distinguished the early amphibian known as Diplocaulus primitive amphibians that have returned to a life spent largely in the water or in moist places. Consequently they show a certain amount of "regressive evolution," such as the secondary development of cartilage in parts of the skeleton that once were com- pletely bony. Some of the Pennsylvanian lepospondyls seem to indicate an ancestry for the salamanders. It is possible that the Gymnophiona or coecilians also were derived from a lepospondyl ancestry, but since no fossils are known, the history of these small, leg- less, tropical amphibians must remain largely a matter of conjecture. Restoration by John C. Cermann. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Colbert, Edwin H. (Edwin Harris), 1905-2001; Knight, Charles Robert, 1874-1953; American Museum of Natural History. New York : Published for the American Museum of Natural History by McGraw-Hill
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Keywords: ., bookauthoramericanmu, bookcentury1900, booksubjectreptilesfossil
