. Animal locomotion or walking, swimming, and flying : with a dissertation on aëronautics. ous bird, and it is worthy of wings act together, or synchronously, as in flying birds ;the feet, on the other hand, are moved alternately. Thewings are wielded with great energy, and, because of theii 96 ANIMAL LOCOMOTKX. semi-rigid rendition, are incapable of expansion. They there-fore present their maximum and minimum of surface bya partial rotation or tilting of the pinion, as in the , and turtle. The feet, which are moved with lessvigour, are, on the contrary, rotated or
. Animal locomotion or walking, swimming, and flying : with a dissertation on aëronautics. ous bird, and it is worthy of wings act together, or synchronously, as in flying birds ;the feet, on the other hand, are moved alternately. Thewings are wielded with great energy, and, because of theii 96 ANIMAL LOCOMOTKX. semi-rigid rendition, are incapable of expansion. They there-fore present their maximum and minimum of surface bya partial rotation or tilting of the pinion, as in the , and turtle. The feet, which are moved with lessvigour, are, on the contrary, rotated or tilted to a very slightextent, the increase and diminution of surface being securedby the opening and closing of the membranous expansion orweb between the toes. In this latter respect they bear a cer-tain analogy to the feet of the seal, the toes of which, as hasbeen explained, spread out or divaricate during extension,and the reverse. The feet of the penguin entirely differfrom those of the seal, in being worked separately, thefoot of one side being flexed or drawn towards the body,. FlG , in the act of swimming, the right foot being fully expanded,md about to give the effective stroke, which is delivered outwards, down-i mis I ml backwards, as represented at r of fig. 50; the left foot being elosed,i 1 • boot to make the return stroke, which is delivered in an inward, up-warda^Kl forward directum, as shown ats of fig. 5CL In rapid^swnnmingthe swan flexes its legs simultaneously and somewhat slowly, it tnenvigorously extends them.—Original. while its fellow is being extended or pushed away from feet, moreover, describe definite curves in opposite direc-tions, the right foot proceeding from within outwards andfrom above downwards during extension, or when it is fullyexpanded and giving the effective stroke ; the left one, whichis moving at the same time, proceeding from without in-wards and from below upwards during flexion, or when it is\\ rtded up, as ha
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Keywords: ., bookcentury1800, bookdecade1870, booksubje, booksubjectphysiology
