[Illustration: FIG. 136.--NOTATION OF THE GALLOP OF FOUR PERIODS IN THE HORSE (AFTER PROFESSOR MAREY).
1, First period; 2, second period; 3, third period; 4, fourth period.]
Thus, we find at the start a right lateral pressure (Fig. 129), next a right diagonal (Fig. 130), then a left lateral; finally, a left diagonal pressure. It is thus that the initial letters L, D, L´, D´ further indicate the notations represented in Fig. 128.
=The Gallop.=--The ordinary gallop is a pace of three phases. The first is characterized by the fact that one hind-limb alone rests on the ground (Fig. 131); in the second the animal is on a diagonal support (Fig. 132); in the third it comes down on a fore-limb (Fig. 133). The body is then raised (Fig. 134), and to this period of suspension succeed anew the three modes of pressure indicated above.
The gallop is said to be from either right or left. In the gallop from the right, the right fore-leg is the more frequently in advance of its neighbour; it is the last to be placed on the ground. The left foot of the posterior biped is the one which commences the action.
An entirely opposite arrangement characterizes the gallop from the left.
[Illustration: FIG. 137.--LEAP OF THE HARE (AFTER G. COLIN).]
The notation reproduced in Fig. 135 corresponds to the gallop from the right. It is there seen, as we pointed out above, that in the first phase the exclusive support of the left hind-foot takes place (1); that afterwards, in the second, commence simultaneously, the pressures of the left fore and the right hind foot (2); this is the left diagonal support; and that finally, in the third, the body comes down on a fore-limb, which is then the right (3); and that for a moment it is on this limb alone that the animal rests.
To these three phases on the notation succeeds an interval; this is the period of suspension.
The gallop of four phases only differs from the preceding in that the foot-fallings of each diagonal biped occur at slight intervals, and give distinct sounds. The notation is reproduced in Fig. 136.
=The Leap.=--The leap is an act by which the body is wholly raised from the ground and projected upwards and forwards to a greater or less distance.
It is prepared for by the flexing of the hind-limbs, which, by being suddenly extended, project the body, and thus enable it to pass over an obstacle.