. Fourteen weeks in zoology. Zoology. CLASS amphibia: okdee anuea. 179 CLASS IV- AMPHIBIA. General Characteristics.—Amphibians have a double life—an immature or tadpole stage passed in the water, during which they breathe by gills; and a mature stage passed in the air, during which they bi-eathe by lungs. To this metamorphosis there are a few exceptions, but the typi- cal species lose the gills and tails by absorption, and develop lungs and limbs. Some retain the tails and others the gills, but all when mature have lungs. As a rule, the tadpoles are herbivorous, the adults carnivorous. 'Tails
. Fourteen weeks in zoology. Zoology. CLASS amphibia: okdee anuea. 179 CLASS IV- AMPHIBIA. General Characteristics.—Amphibians have a double life—an immature or tadpole stage passed in the water, during which they breathe by gills; and a mature stage passed in the air, during which they bi-eathe by lungs. To this metamorphosis there are a few exceptions, but the typi- cal species lose the gills and tails by absorption, and develop lungs and limbs. Some retain the tails and others the gills, but all when mature have lungs. As a rule, the tadpoles are herbivorous, the adults carnivorous. 'Tails and gills transient. Anura, Fiog, Toady etc Tails PERMANENT AND GILLS TRANSIENT. Urodela, Salamander, etc. Tails and gills feruanunt. Amphipneusta, Siren, etc. ORDER ANURA. General Characteristics.—The Tailless Amphibians are distinguished by ^^^^^ their broad heads, naked skin, prominent but retractile eyes, and, in the adult state, lack of tails. The eggs are laid' and hatched in the water. The young tad- pole resembles a little fish, with a large head and compressed tail, but no limbs. Soon gills (branchiffi) appear; and then small, vascu- lar tufts aid respiration by extracting air from the water that passes through the mouth and out of temporary slits. Tadpole Skeleton of a Frog. Fig. 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 Steele, Joel Dorman, 1836-1886. New York, Chicago [etc. ] A. S. Barnes & Company
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectzoology, bookyear1872
