. The bird; its form and function . Fig 41—Common Fowl, showing relation of the bony framework or skeletonto the contour of the body. Notice large eye, long and mobile neck theknee wholly within the body plumage, and the well-developed keel hintmgof ancestors with strong powers of flight. 1/4 natural size. 6? 66 The Bird hints of the way it originated. In the lowest of fish-Ukecreatures—the Amphioxus, a tiny animal, an inch or twoin length, living in the sand along our shores—there isa thread-like cord of a gelatinous substance (not carti-lage, however) extending down the back, known as thenot
. The bird; its form and function . Fig 41—Common Fowl, showing relation of the bony framework or skeletonto the contour of the body. Notice large eye, long and mobile neck theknee wholly within the body plumage, and the well-developed keel hintmgof ancestors with strong powers of flight. 1/4 natural size. 6? 66 The Bird hints of the way it originated. In the lowest of fish-Ukecreatures—the Amphioxus, a tiny animal, an inch or twoin length, living in the sand along our shores—there isa thread-like cord of a gelatinous substance (not carti-lage, however) extending down the back, known as thenotochord. He looks like some kind of worm, but thislittle gristle is his badge of nobility and lifts him clear. Fig. 42.—Amphioxus, one of the lowest vertebrates, with a mere thread ofgristle foreshadowing the back-bone of higher animals. This creature bur-rows in the sand along the Atlantic coast. of corals, snails, insects, and worms, into the realm ofback-boned animals. This notochord lies underneath athin white line which is all the spinal chord he has, and,at the front end of this, a tiny dot of pigment standsfor brain, eye, and ear. Indeed Amphioxus has neitherskull, brain, nor limbs. The history of the back-bone, like human history, isnot altogether a majestic upward evolution; it has itstragedies and set-backs, its hopes and failures. In thewaters along our Northern seashores are creatures, somesponge- or lichen-like, others with strange bulb-like bodies The Framework of the Bird 67 growing on the end of long stalks. We call them almostplants. But they hold a secret from the crabs and snailswhich crawl about, and when the fishes brush against
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbirds, bookyear1906
