. Animal locomotion, or Walking, swimming, and flying, with a dissertation on aëronautics. Animal locomotion; Aeronautics. 34 ANIMAL LOCOMOTION. ties of quadrupeds, bipeds, etc. in walking; in the move- ments of the tails and fins of fishes, whales, etc. in swimming; and in the movements of the wings of insects, bats, and birds in flying. The straight and oblique muscles are usually found together, and co-operate in producing the movements in question; the amount of rotation in a part always increasing as the oblique muscles preponderate. The combination of ball-and-socket and hinge-joints, wi
. Animal locomotion, or Walking, swimming, and flying, with a dissertation on aëronautics. Animal locomotion; Aeronautics. 34 ANIMAL LOCOMOTION. ties of quadrupeds, bipeds, etc. in walking; in the move- ments of the tails and fins of fishes, whales, etc. in swimming; and in the movements of the wings of insects, bats, and birds in flying. The straight and oblique muscles are usually found together, and co-operate in producing the movements in question; the amount of rotation in a part always increasing as the oblique muscles preponderate. The combination of ball-and-socket and hinge-joints, with their con- comitant oblique and longitudinal muscular cycles (the former occurring in their most perfect forms where the extremities are united to the trunk, the latter in the extremities them- selves), enable the animal to present, when necessary, an exten- sive resisting surface the one instant, and a greatly diminished and a comparatively non-resisting one the next. This arrange- ment secures the subtlety and nicety of motion demanded by the several media at different stages of progression. The travelling surfaces of Animals modifiecl and adai^ted to the medium on or in tvhich they move.—In those land animals which take to the water occasionally^ the feet, as a. Fig. 10. Fig. 11. Fig. 12. Fig. 13. Fig. 14. Fig, 10.—Extreme form of com]>ressed foot, as seen in the deer, ox, etc., adapted specially for land ivRTiiiii.—Original. Fig, 11.—Extreme form of expanded foot, as seen in the Ornitlwrhynclviis, etc., adapted more particularly for i^wmimm^. —Original. Figs. 12 and 13.—Intermediate form of foot, as seen in the otter (lig. 12), frog (fig. 13), etc. Here the foot is equally serviceable in and out of the water,—Original. ? . Fig. 14. —Foot of the seal, which opens and closes in the act of natation, the organ being folded upon itself during the non-effective or return stroke, and expanded during the effective or forward stroke. Due advantage is taken of
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectaeronau, bookyear1874
