. Animal locomotion, or Walking, swimming, and flying, with a dissertation on aëronautics. Animal locomotion; Aeronautics. Fig. 49.—Foot of Grebe (Podiceps). In this foot each toe is provided with its swimming membrane ; the membrane being closed wlien tiie foot is flexed, and expanded when the foot is extended. Compare with foot of swan (fig. 48), where the swimming membrane is continued from the one toe to the other.—(After Dallas.) consists of three swimming toes, each of which is provided with a membranous expansion, which closes when the foot is being drawn towards the body during the bac
. Animal locomotion, or Walking, swimming, and flying, with a dissertation on aëronautics. Animal locomotion; Aeronautics. Fig. 49.—Foot of Grebe (Podiceps). In this foot each toe is provided with its swimming membrane ; the membrane being closed wlien tiie foot is flexed, and expanded when the foot is extended. Compare with foot of swan (fig. 48), where the swimming membrane is continued from the one toe to the other.—(After Dallas.) consists of three swimming toes, each of which is provided with a membranous expansion, which closes when the foot is being drawn towards the body during the back stroke, and opens out when it is being forced away from the body during the effective Fig. 50.—Diagram representing the double Avave<l track described by the feet of swimming birds. Compare with figs. 18 and 19, pp. 3T and 39, and with 32, li. {"iS.—Original. In swimming birds, each foot describes one side of an ellipse when it is extended and thrust from the body, the other side of the ellipse being described when the foot is flexed and drawn towards the body. The curve described by the right foot when pushed from the body is seen at the arrow r of fig. 50 ; that formed by the left foot when drawn towards the body, at the arrow s of the same figure. The curves formed. 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 Pettigrew, James Bell, 1834-1908. New York, D. Appleton & company
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectaeronau, bookyear1874
