. Zoology : for students and general readers . Zoology. ANATOMY OF THE GUNNER. 439 The walls of the auricle are comparatively thin ; the auriculo- ventricular orifice is provided with valves, which prevent the blood flowing back into the auricle. The walls of the ventricle are thick and very muscular ; from the upper end of the ventricle close to the base of the auricle springs the iidbus arteriosus, a muscular cylinder, which, running hori- zontally forward, passes out through the pericardium, and is continued as the less muscular aorta (A) underneath the branchial arches along the median lin
. Zoology : for students and general readers . Zoology. ANATOMY OF THE GUNNER. 439 The walls of the auricle are comparatively thin ; the auriculo- ventricular orifice is provided with valves, which prevent the blood flowing back into the auricle. The walls of the ventricle are thick and very muscular ; from the upper end of the ventricle close to the base of the auricle springs the iidbus arteriosus, a muscular cylinder, which, running hori- zontally forward, passes out through the pericardium, and is continued as the less muscular aorta (A) underneath the branchial arches along the median line ; the aorta gives off branches on both sides, one to each arch to supply the brau- chise; the vessels after ramifying are gathered together, to again form a single trunk, which passes backward immedi-. Fig. 399.—Anatomy of the Gunner, male. Z, lateral line ; ffi, heart; G, pharynx ; Ps, pseudobranchia ; f>p, spleen ; S, air-bladder : Ki, Ki\ kidneys ; N; b] ; T, tes- tis ; A, aorta ; JB, brain ; In, intestine ; Zi, liver ; G, gills.—Drawn by C. S. Minot. ately underneath the spinal column ; it is called the descend- ing aorta. The body and pericardial cavities are called serous, because their lining membranes are always moist with serum, a watery fluid, very much like blood-plasma. The lining of the body^ cavity is named the peritoneum, and forms a continuous cov- ering around the viscera. It is important to observe that the various organs simply project into the body-cavity and do not lie really inside of it. In fishes we find the disposition of the parts to correspond more closely with the fundamental type of Vertebrate structure than it does in higher forms, in which further modifications have supervened. The pharynx still has its distinctive character ; the pericardium lies at the. 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 n
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectzoology, bookyear1879
