File:The bird, its form and function (1906) (14569070898).jpg

Identifier: birditsformfunct07beeb (find matches)
Title: The bird, its form and function
Year: 1906 (1900s)
Authors: Beebe, William, 1877-1962
Subjects: Birds Birds
Publisher: New York : Henry Holt
Contributing Library: Internet Archive
Digitizing Sponsor: Internet Archive

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
nd in appearancebirds eggs may be compared with gems; indeed the shellitself is almost wholly composed of mineral matter. But,far from being an inanimate crystal, an egg shelters oneof the marvels of the world—an embryo bird. Thegaudy sea-shell cloaks a slimy snail, but from the beautifulegg of a bird emerges a greater beauty. Reptiles lay white eggs whose shells are not brittle,but, when broken, curl up like a celluloid film. Someof these reptilian eggs are oblong in shape, but most arespherical and the great majority are deposited in theground, or under bark, and are hatched by the heat of thedecaying vegetation or by the direct rays of the sun.Thus we see that there is little need for variation inshape or colour. Among birds, however, we find verydifferent conditions. As we know that birds have evolved from reptiles,we have a right to suppose that the early forms of birdslaid white, leathery eggs, perhaps in hollow trees; butthe power of flight has taken birds entirely out of the
Text Appearing After Image:
Fig. 342.—Comparison of eggs of reptiles and birds,(a) Egg of Hen. (b) Egg of Skate, (c) Egg of Snake, (d) Egg of Turtle,(e) Egg of Alligator. 429 43° The Bird reptilian horizon, and greatly altered all the conditionsof their life. The history of the egg of a bird, from thetime it is laid until it hatches, has an all-important effecton its form, colour, and even upon the number of eggslaid. This is not strange when we consider that everyminute of the birds life is open to many dangers, andthat the egg stage—that bridging over of generations—is a most precarious period. That which adds the greatest interest to anything isthe why of it, and a vast collection of eggs, beautifulthough they are, yet, if ignorantly looked at, is worse thanuseless. Why one bird lays twenty eggs and anotherbut two; why one birds eggs are white, anothers of variedcolours, we will never learn from blown museum speci-mens. Not until we have the patience and skill to watchand to find the most deadly enemie

Note About Images