. A first book of zoology [microform]. Zoology; Zoologie. H ZOOLOGY tilizing substance and egga, but just as in plants the ova are generally fertilized by means of the pollen from another plant, so also in the worm cross-fertilization occurs. When the eggs are about to be laid, the skin in the clitellum region actively secretes or produces a fluid which exposure to the air converts into an elastic substance. Thus the clitellum region appears to be surrounded by a broad elastic ring or cocoon. The earthworm next begins to wriggle backwards out of the cocoon, and so the latter is pushed nearer a
. A first book of zoology [microform]. Zoology; Zoologie. H ZOOLOGY tilizing substance and egga, but just as in plants the ova are generally fertilized by means of the pollen from another plant, so also in the worm cross-fertilization occurs. When the eggs are about to be laid, the skin in the clitellum region actively secretes or produces a fluid which exposure to the air converts into an elastic substance. Thus the clitellum region appears to be surrounded by a broad elastic ring or cocoon. The earthworm next begins to wriggle backwards out of the cocoon, and so the latter is pushed nearer and nearer towards the mouth. While • I M. Vb cocoon clUeUum,' Fio. 9.—A. Earthworm, front end. showing coccwn; Bi and C Cocoons of two differtnt kinds of earthworms ( x about 4). the elastic ring is passing over segment fourteen the eggs are laid and get between the cocoon and the earthworm's body. While the eggs are being laid, a nutritive fluid and also some of the stored-up fertilizing substance are squeezed from the body and mix with the eggs. The ends of the cocoon close up as they pass beyond the mouth. In this way the eggs are fertilized, protected by an. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Burlend, T. H; Cornish, George A. (George Augustus), 1872-1960. Toronto : Macmillan
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1915
