. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. Opening Fig. 673. A teleost fish, Notosema, showing a kink in the lateral line, which thus may avoid currents pro- duced in the water by movements of the pectoral fin. (After Goode and Bean.). ^__-Tube „»Sensory '"' Cells Nerve Fig. 674. Two organs of Lorenzini from a dogfish, Scyllium. (After Haller.) The presence of abundant mucus in the lateral-line system and related pit organs led formerly to the idea that these organs were glandular and primaril
. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. Opening Fig. 673. A teleost fish, Notosema, showing a kink in the lateral line, which thus may avoid currents pro- duced in the water by movements of the pectoral fin. (After Goode and Bean.). ^__-Tube „»Sensory '"' Cells Nerve Fig. 674. Two organs of Lorenzini from a dogfish, Scyllium. (After Haller.) The presence of abundant mucus in the lateral-line system and related pit organs led formerly to the idea that these organs were glandular and primarily secretory in function, but the discovery by Leydig in 1850 that they have a sensory rather than a motor nerve supply placed them definitely in the category of sense organs. Subsequent experimentation on fishes, by cutting different nerve supplies, showed that these sense organs make the animal receptive to coarse vibrations agitating the surrounding medium, as well as to the sustained impact of water in the form of currents. By means of such organs the fish is enabled to face against the water flow, even in darkness or in turbid waters when no "landmarks" are visible, and so to maintain its position without being constantly carried down-stream, or away with flowing tides and currents. Rheoreceptors no doubt also help in making a fish aware of the approach of enemies which agitate the water by swimming movements, producing low vibrations that act as warning 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 Walter, Herbert Eugene, b. 1867; Sayles, Leonard Perkins, 1902-. New York : Macmillan Co.
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Keywords: ., bookcentury1900, booksubjectanatomycomparative, booksubjectverte
