. Outlines of zoology. Zoology. AMPHIBIANS. 5 they differ from them in being "cold-blooded," and in many other ways. Amphibians.—The Amphibians, such as frogs and newts, were once regarded— by Cuvier—as naked Reptiles, but a more accurate classification has linked them rather to the Fishes. Thus Huxley grouped Birds and Reptiles together as Sauropsida; Amphibians and Fishes together as. Fig. 5.—Salamander, an Amphibian. Ichthyopsida—for reasons which will be afterwards stated. Amphibians mark the transition from aquatic life, habitual among Fishes, to terrestrial life, habitual a
. Outlines of zoology. Zoology. AMPHIBIANS. 5 they differ from them in being "cold-blooded," and in many other ways. Amphibians.—The Amphibians, such as frogs and newts, were once regarded— by Cuvier—as naked Reptiles, but a more accurate classification has linked them rather to the Fishes. Thus Huxley grouped Birds and Reptiles together as Sauropsida; Amphibians and Fishes together as. Fig. 5.—Salamander, an Amphibian. Ichthyopsida—for reasons which will be afterwards stated. Amphibians mark the transition from aquatic life, habitual among Fishes, to terrestrial life, habitual among Reptiles, for while almost all Amphibians have gills—in their youth at least—all the adults have lungs, and some retain the gills as well. In having limbs which are fingered and toed, and thus very different from fins, they resemble Reptiles. But the two fcetal membranes characteristic of the embryonic life of higher Vertebrates are not present in Amphibian embryos, and the general absence of an exoskeleton in modern forms is noteworthy. Fishes.—The members of this class are as markedly adapted to life in the water as birds to life in the air. The Fig. 6.—Queensland dipnoan [Ceratodus) tail usually forms the locomotor organ, and the limbs are fins. There are also unpaired median fins supported by fin rays. All have permanent gills borne by bony or gristly. 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 Thomson, J. Arthur (John Arthur), 1861-1933. Edinburgh, Glasgow and London, H. Frowde and Hodder & Stoughton
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Keywords: ., bookauthorth, bookcentury1800, bookdecade1890, booksubjectzoology
