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Rh parts, but silvery beneath. Some however are pied. Old males usually have a large spot of pale grey on the front of the head, when they are said to be "grey-headed." The eye is situated just above the angle of the mouth; and over this at the junction of the head with the body, there is an elevation called the "bunch of the neck;" from hence the outline of the back is nearly straight, to within one third of its length from the tail, where there is a larger prominence, called the "hump;" it now rapidly tapers away to the tail, and this slender part is technically distinguished as the "small," while the huge tail spreading widely on each side bears the name of "flukes."

The motions of this enormous animal are exceedingly curious; when moving perfectly at leisure, he swims slowly along, just beneath the surface, effecting his progress by gently striking the fluid with his tail from side to side obliquely. The bunch and hump may be seen above the water; and by the disturbance which they cause in cutting the surface, some foam is produced, by which an experienced whaler can judge, even at some miles’ distance, how fast the animal is going. When alarmed, however, or from any cause inclined to increase his velocity, he uses a very different mode of progression. The broad tail now strikes the water upward and downward alternately with great force; at every blow downward the fore part sinks several yards into the water, while by the force of the upward blow, the head is thrust entirely out of the water. A whale can swim in this way, the head alternately appearing and disappearing, which the seamen call "going head out," at the rate of twelve miles an hour.