the elbow the secondary quills are merely glued or stuck at the very ends to the arm bone, the ulna. The thumb appears as a hook in some birds ; in others it has an outgrowth of a short quill, " a spurious primary." Now the wing of a bat is arranged on a fore leg or a fore arm, but on a different plan from the bird. The five fingers are very long, and between them is stretched a most delicate membrane, that ex-tends backward around the body from both sides of it, and takes in the hinder legs and tail in all insect-eating bats. Fruit-eating bats, in some instances, do not have the wings extending backward to the tail.
There is no other animal with such an arrangement for flight. In the far East there is a tree-frog with very long toes on all four feet, and these, being webbed, are used not for swimming, nor properly for flying, but as aids to jumping, like our so-called flying-squirrel. When this frog desires to jump from one tree to another within range, he makes the leap, spreads his legs and toes, and glides forward and downward ; but this is not true flying. Our bat is an expert on the wing; no bird is quite his equal when it comes to short turns, as any one knows who has tried to bring one down in a room. The wings are richly supplied with