LOCOMOTION OF ANIMALS ON SOLIDS. 179 



segments of this limb are, accordingly, straighter, or less angular, than those 

 of the hinder limb. 



In the larger and heavier quadrupeds, such as the elephant, rhinoceros, and 

 hippopotamus, the segments of the limbs are shorter, thicker, and more per- 

 pendicular in their direction ; peculiarities which increase the bearing powers 

 of the limbs, but diminish their locomotive capabilities, as manifest in the 

 slower and more unwieldy actions of those bulky creatures. * In the Equine, 

 and more active of the 'Ruminant, animals, the limbs are proportionally more 

 slender, longer, and have the segments placed at more acute angles, especially, 

 as already noticed, in the hinder limb ; of these, however, the horse is the best 

 fitted of all quadrupeds for rapid and energetic motion, and for draught, and 

 constitutes the exemplar of quadruped locomotion. The Flying Childers ran 

 at the rate of 4 miles in 6 minutes and 2 seconds, or about 40 miles an hour, 

 whilst the pace of Eclipse was 56 miles an hour, or nearly a mile in a minute. 

 This swiftness of the horse is mainly owing to the solidity of the extremities 

 of its limbs, which consist of an enlarged and expanded single toe, or finger, 

 which carries the broad and solid hoof. In the heavier Pachydermata, the toes 

 are more numerous, being three in the rhinoceros, four in the hippopotamus, 

 and in the elephant five, inclosed in one mass ; but the foot, though broader 

 for carrying weight, loses in firmness. In the cleft foot of the Ruminants, the 

 number of digits is four, two bearing the proper bisulcate hoof, and two the 

 spurious hoofs ; the parts of the foot are thus easily spread out, so as to give 

 a greater hold upon soft ground ; but it exhibits a proportionate degree of 

 weakness. 



The movements of quadrupeds are named the walk, the amble, the trot, the 

 canter, and the gallop. In the act of walking, a quadruped first moves forward 

 one fore-leg, and then the opposite hind-leg ; next the other fore-leg is advanced, 

 and then the opposite hind-leg, and so on ; these several movements being 

 perfectly distinguishable, and following in regular sequence, however rapidly 

 the animal may walk. The centre of gravity not only moves forwards, but 

 rises and falls, and moves obliquely from side to side, according as the one or 

 the other fore-foot is being advanced ; moreover, one foot only is off the ground 

 at the same moment, the advancing fore-foot always being placed down before 

 the opposite hind-foot is raised, and the latter being placed down before the 

 opposite fore-foot is raised. In trotting, the fore and hind limbs of the opposite 

 sides, are advanced simultaneously, and they are raised from the ground, and 

 placed upon it again, also simultaneously ; so that the centre of gravity is 

 supported alternately upon the right fore-leg and left hind-leg, and then upon 

 the left fore-le^ and "right hind-leg ; and in this movement there is much less 

 lateral oscillation, indeed scarcely any at all, in comparison with the walking 

 movement, as the rider on horseback practically knows. In galloping, both 

 fore-legs are lifted from the ground almost simultaneouly, and the body of the 

 animal is projected upwards and forwards, by the extension of both hind limbs ; 

 the weight of the body then descending, is received on both fore-legs, which 

 are brought to the ground again, almost at the same instant of time, when the 

 hind-legs are once more brought under the body, and placed almost simulta- 

 neously upon the ground, so as to be ready for the performance of another spring. 

 Cantering is a sort of a slow, measured gallop, in which a longer interval of 

 time elapses between the placing of the two fore-legs and the two hind-legs- 

 upon the ground. In the canter one or other pair of legs only, is raised from 

 the ground at any one instant ; so that the body of the animal is always sup- 

 ported by one or other pair of limbs ; but in the gallop, there is a period, short 

 in the slow gallop, but more and more prolonged in the rapid gallop, as in 

 the active strides of a race-horse, when all four limbs are off the ground, and 

 the animal is swinging in the air. 



In the Carnivora, the mode in which the feet are used in progression, has 

 led to a threefold division of that class into the digitigrade, such as the cat and 

 doo- tribes ; the plantigrade, represented by the bears ; and the palmigrade, 

 natatory, or swimming Carnivora, exemplified by the seals. 



Amongst the quadruped Mammalia, a well-marked distinction may be 

 drawn, as regards their locomotive powers and habits, between those which 

 possess a clavicle, and those which do not. As already stated, in the larger 



