. Annals of the New York Academy of Sciences. Science. GREGORY, QUADRUPEDAL LOCOMOTION 283 from a comparison of the photographs (Fig. 1) of an ambling ele- phant and of a galloping horse, it seems probable that the straightness of the limbs in graviportal animals has been evolved pari passu with the short rectigrade feet and with an ambling even gait, in combination with a long stride of minimal acceleration increment (p. 274). Conversely, the bent or angulate character of the limbs in the horse and other cur- sorial animals is correlated in part with the very long, slender unguli- grade feet
. Annals of the New York Academy of Sciences. Science. GREGORY, QUADRUPEDAL LOCOMOTION 283 from a comparison of the photographs (Fig. 1) of an ambling ele- phant and of a galloping horse, it seems probable that the straightness of the limbs in graviportal animals has been evolved pari passu with the short rectigrade feet and with an ambling even gait, in combination with a long stride of minimal acceleration increment (p. 274). Conversely, the bent or angulate character of the limbs in the horse and other cur- sorial animals is correlated in part with the very long, slender unguli- grade feet and with a bounding galloping or trotting gait, in combination with a long, very rapid stride of maximal acceleration Fig. 5.—"Cursorial" adaptations for the run, gallop, etc., in the Neohipparion Iii other words, the use and structure of the feet have been the teleo- logical dominants which have determined the diverse modifications in the musculature, proportions and angulation of the proximal segments of the limbs, just as in early stages of aquatic adaptation in reptiles (e. g., Thalattosuchia, ISTothosauria, etc.) the aquatic habits are reflected more clearly in the feet or distal segments rather than in the proximal limb segments. MECHANICS OF THE FOOT IN GRAVIPORTAL AND CURSORIAL FORMS Comparing the structure and function of the graviportal and cursorial types of feet, we see (Figs. 3 and 4) that, in the elephant, the very mas- sive gastrocnemius and soleus muscles are attached at a wide angle to the massive calcaneum, while the foot itself is very short. In the position shown in Fig. 3 (II) and as compared with conditions in the horse, this. 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 New York Academy of Sciences. New York, New York Academy of Sciences
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectscience, bookyear1877
