Page:Bird-lore Vol 08.djvu/82

 58 Bird- Lore When swimming, these birds not only use the flat side of the leg as a cut -water; but their toes curl and uncurl with a slight oblique revolving motion, like the blades of a propeller. When drawn forward through the water they are rolled up into very small compass, and then instantly spread out as widely as possible on the return stroke. To the eye it seems as if this bird was constantly grasping something tangible in the water and thrusting it behind. For many reasons the most interesting of all birds' feet are those of the Ostriches and their allies. When one trains in college for a long- distance race, the first rule to observe is, — run wholly on the ball of the foot, never touch your heels to the ground. Untold centuries ago, wise old Nature whispered the very same direction to those of her children who had the most need to run for their lives in life's great race, and down through the ages some of them have never broken training. Hence, when an animal acquires great speed in running or leaping, there is a tendency for one toe to become greatly enlarged at the expense of the others, as is seen in the case of the horse, the kangaroo and the Ostrich. In the horse only the middle toe is functional, the second and fourth having degenerated into the small splint bones at the side of the leg. The kangaroo progresses on the fourth and fifth toes, the second and third being small and skin- bound. The Ostrich has but two toes, one of which, the third, as in the case of the horse, is very large and armed with a thick claw, which grows close to the toe. This toe supports most of the bird's weight, while the fourth, or outer toe, is only one- quarter as large, and, indeed, it bids fair to disappear altogether in the course of time; even now the diminutive nail (when it is pres- ent) is only as large as the claw of a chicken. The power of the Ostrich to defend FEET OF black-footed penguin. itself by kicking is well known, but the claw FR0M LIFE FOOT OF BROWN PELICAN