. The biology of birds. Birds. of the windpipe. The cartilages of the larynx are biologi- cally interesting, for they are the transformed representatives of branchial arches—an instance of a common method of organic evolution, mak- ing a new thing out of an older thing. The larynx and the vocal cords began in Amphibians. The trachea is sup- ported by bony " rings," usually, but not always, complete. In mammals the rings are gristly. The trachea is sometimes much longer than the neck ; it is coiled inside the breastbone in the Whooper Swan, outside the breastbone in the Capercailzie.
. The biology of birds. Birds. of the windpipe. The cartilages of the larynx are biologi- cally interesting, for they are the transformed representatives of branchial arches—an instance of a common method of organic evolution, mak- ing a new thing out of an older thing. The larynx and the vocal cords began in Amphibians. The trachea is sup- ported by bony " rings," usually, but not always, complete. In mammals the rings are gristly. The trachea is sometimes much longer than the neck ; it is coiled inside the breastbone in the Whooper Swan, outside the breastbone in the Capercailzie. It is moved by two sterno-tracheal muscles attached to the front of the breast-bone. The syrinx or song- box at the base of the trachea is absent in os- triches, storks, and some —Part of breathing system of a vulturCS. It is an en- From a specimen, i, the tongue; i „. r .1 u„„„ ^f 2, the glottis or entrance to windpipe; I'^lfgement of the base of 3, the voiceless larynx; 4, posterior the trachea and of the " iiorns " of the hvoid, to which some r-^. „^ ^^ +1,^^^ ,-,*^rTo r^f tongue muscles are attached; 5, the ^rst tWO or three nngS ot windpipe; 6, the syrinx or song-box; the bronchial tubes, and 8* o^^^he kings'' """'''"^ '^' '^'""''' ^^ contains the stretched vocal cords which vibrate more or less musically when the expired air passes rapidly over them. There is a somewhat complex skeleton and musculature. There may be an asymmetrical accessory chamber or labyrinth in addition to the main cavity or. Ftr;. 30 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 Thomson, J. Arthur (John Arthur), 1861-1933. New York : Macmillan
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbirds, bookyear1923
