. On the anatomy of vertebrates. Vertebrates; Anatomy, Comparative; 1866. G3S ANATOMY OF VERTEBRATES. 446 symmetrical pair of longisli simple sacs, extending from the pharynx on each side of the cjesojthagus to tlie beginning of the liver: the left division soon begins to exceed the right in length, and then seems to monopolise the power of growth. The common stem or neck of the pulmonary sacs elongates, contracts, and Ijegins to show traces of the transverse cartilages; and at about the latter third of the developemental period the right lung appears as a mere appendage to the beginning of th
. On the anatomy of vertebrates. Vertebrates; Anatomy, Comparative; 1866. G3S ANATOMY OF VERTEBRATES. 446 symmetrical pair of longisli simple sacs, extending from the pharynx on each side of the cjesojthagus to tlie beginning of the liver: the left division soon begins to exceed the right in length, and then seems to monopolise the power of growth. The common stem or neck of the pulmonary sacs elongates, contracts, and Ijegins to show traces of the transverse cartilages; and at about the latter third of the developemental period the right lung appears as a mere appendage to the beginning of the left. The appear- ance of malpighian bodies, as minute red points on part of the surface of the primordial kidneys, is the first indication of the developement therefrom of the kidneys: these grow between the jH'imordial kidneys and the vertebra? at the hindmost end of the abdominal cavity. The testis, or ovary, is differentiated from the ventral surface of the fore-part of the primordial glands : at one period of developement the primor- dial ducts coexist with the sperm-duct and ureters. Four or five ducts emerge from the liver and unite into a com- mon one before communicating with the intestine ; a similar duct, proceed- ing from the common one, expands at its opposite end into the gall-bladder. This remains near the pylorus: the hepatic ducts elongate as the intestine recedes on the growth of the snake. The spleen first appears as an append- age to the narrow end of the j^ancreas. In the male embryo, the two bifurcate penes project from the cloaca before the period of extrication. Figure 446 shows the posterior half of the embryo of the Viper at a late period of developement. The yolk bag, fl, is mucli reduced in size, but is not yet taken into the abdominal cavity ; h is the portion of the amnios adherent to the vitclliclo ; c is the short pedicle, including part of (/, the ductus Aitcllo-intestinalis, which as- cends to terminate at e, lietween the longitudmal folds of
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Keywords: ., bookauthorowenrichard18041892, bookcentury1800, bookdecade1860
