. Comparative zoology, structural and systematic : for use in schools and colleges. Zoology; Anatomy, Comparative; Physiology, Comparative. VERTEBRATA. 317 long, ribbon-like pectoral and ventral fins, set far apart; two auricles, and one ventricle; and, besides gills, a cellu- lar air-bladder, which is used as a lung. The representatives are Ceratodus from Australia, Pro- tqpterus from Africa, and Zepidosiren from Brazil. Class II.—Amphibia. These cold-blooded Vertebrates are distinguished by having gills when young, and true lungs when adult. They have no fin-rays, and the limbs, when present
. Comparative zoology, structural and systematic : for use in schools and colleges. Zoology; Anatomy, Comparative; Physiology, Comparative. VERTEBRATA. 317 long, ribbon-like pectoral and ventral fins, set far apart; two auricles, and one ventricle; and, besides gills, a cellu- lar air-bladder, which is used as a lung. The representatives are Ceratodus from Australia, Pro- tqpterus from Africa, and Zepidosiren from Brazil. Class II.—Amphibia. These cold-blooded Vertebrates are distinguished by having gills when young, and true lungs when adult. They have no fin-rays, and the limbs, when present, have the same divisions as those of higher animals. The skin is soft, and generally naked, and the skeleton is ossified. The skull is flat, and articulates with the spinal column by two condyles. There is no distinct neck; and the ribs are usually small or wanting. The heart consists of two auricles and one ventricle. All undergo metamorphosis upon leaving the egg, passing through the " tadpole" state. They commence as water-breathing larvae, when they re- semble Fishes in their respiration, circulation, and locomo- tion. In the lowest forms, the gills are retained through life; but all others have, when mature, lungs only, the gills disappearing. The cuticle is frequently shed, the mode varying with the habits of the The com- mon Frog, the type of this class, stands intermediate be- tween the two extremes of the vertebrate series; no fun- damental part is excessively developed. There are about four hundred and fifty liv- ing species, grouped in four orders: 1. Urodela have a naked skin, a tail, and two or four limbs. Some retain their gills through life, as the ^ Head and G\\)&(AMenobranchu8. Cayuga. 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 Orton, James, 1830-1877; Birge
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1883
