Page:The Worst Journey in the World volume 1.djvu/435

Rh visited and Emperor eggs secured is graphically told in The Winter Journey. The question now arises, Has 'the weirdest bird's-nesting expedition that has ever been made' added appreciably to our knowledge of birds?

"It is admitted that birds are descended from bipedal reptiles which flourished some millions of years ago—reptiles in build not unlike the kangaroo. From Archaeopteryx of Jurassic times we know primeval birds had teeth, three fingers with claws on each hand, and a long lizard-like tail provided with nearly twenty pairs of well-formed true feathers. But unfortunately neither this lizard-tailed bird, nor yet the fossil birds found in America, throw any light on the origin of feathers. Ornithologists and others who have devoted much time to the study of birds have as a rule assumed that feathers were made out of scales, that the scales along the margin of the hand and forearm and along each side of the tail were elongated, frayed and otherwise modified to form the wing and tail quills, and that later other scales were altered to provide a coat capable of preventing loss of heat. But as it happens, a study of the development of feathers affords no evidence that they were made out of scales. There are neither rudiments of scales nor feathers in very young bird embryos. In the youngest of the three Emperor embryos there are, however, feather rudiments in the tail region,—the embryo was probably seven or eight days old—but in the two older embryos there are a countless number of feather rudiments, i.e. of minute pimples known as papillae.

"In penguins as in many other birds there are two distinct crops of feather papillae, viz.: a crop of relatively large papillae which develop into prepennae, the forerunners of true feathers (pennae), and a crop of small papillae which develop into preplumulae, the forerunners of true down feathers (plumulae).

"In considering the origin of feathers we are not concerned with the true feathers (pennae), but with the nestling feathers (prepennae), and more especially with the papillae from which the prepennae are developed. What we want to know is, Do the papillae which in birds develop