. A manual of zoology. Zoology. IV. INSECTA 401 The respiratory organs are tracliea: (figs. 437, 438) which resemble the trachea of man only in that they are tubes filled with air, and kept from collapse by firm walls. They open to the exterior by openings {spiracles, stigmata) on the sides of the body. They are inpushings of the skin and consequently have the same structure, an epithelium and an outer chitinous layer. The latter lines the lumen of the tubes, and since it must Ije thin to permit the passage of gases (oxygen, carljon dioxide), and at the same time firm, to keep the tubes open,
. A manual of zoology. Zoology. IV. INSECTA 401 The respiratory organs are tracliea: (figs. 437, 438) which resemble the trachea of man only in that they are tubes filled with air, and kept from collapse by firm walls. They open to the exterior by openings {spiracles, stigmata) on the sides of the body. They are inpushings of the skin and consequently have the same structure, an epithelium and an outer chitinous layer. The latter lines the lumen of the tubes, and since it must Ije thin to permit the passage of gases (oxygen, carljon dioxide), and at the same time firm, to keep the tubes open, it is thrown into folds which usually pursue a spiral course. The turns of the spiral are so close that it gives the tubes a. 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 Hertwig, Richard, 1850-1937; Kingsley, J. S. (John Sterling), 1854-1929, ed. and tr. New York, H. Holt
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
