Animal Locomotion; or, walking, swimming, and flying / With a dissertation on aëronautics

by James Bell Pettigrew

[32] In draught horses the legs are much wider apart than in racers; the legs of the deer being less widely set than those of the racer.

[33] In the apteryx the wings are so very small that the bird is commonly spoken of as the “wingless bird.”

[34] “The posterior extremities in both the lion and tiger are longer, and the bones inclined more obliquely to each other than the anterior, giving them greater power and elasticity in springing.”

[35] “The pelvis receives the whole weight of the trunk and superposed organs, and transmits it to the heads of the femurs.”

[36] The spreading action of the toes is seen to perfection in children. It is more or less destroyed in adults from a faulty principle in boot and shoemaking, the soles being invariably too narrow.

[37] The brothers Weber found that so long as the muscles exert the general force necessary to execute locomotion, the velocity depends on the size of the legs and on external forces, but not on the strength of the muscles.

[38] “In quick walking and running the swinging leg never passes beyond the vertical which cuts the head of the femur.”

[39] “The number of steps which a person can take in a given time in walking depends, first, on the length of the leg, which, governed by the laws of the pendulum, swings from behind forwards; secondly, on the earlier or later interruption which the leg experiences in its arc of oscillation by being placed on the ground. The weight of the swinging leg and the velocity of the trunk serve to give the impulse by which the foot attains a position vertical to the head of the thigh-bone; but as the latter, according to the laws of the pendulum, requires in the quickest walking a given time to attain that position, or half its entire curve of oscillation, it follows that every person has a certain measure for his steps, and a certain number of steps in a given time, which, in his natural gait in walking, he cannot exceed.”

[40] Cyc. of Anat. and Phy., article “Motion.”

[41] The lepidosiren is furnished with two tapering flexible stem-like bodies, which depend from the anterior ventral aspect of the animal, the siren having in the same region two pairs of rudimentary limbs furnished with four imperfect toes, while the proteus has anterior extremities armed with three toes each, and a very feeble posterior extremity terminating in two toes.