. Animal forms; a second book of zoology. Zoology. THE WOKMS 59 gether by elastic bands. A sac, the cocoon, is thus pro- duced, containing the eggs and a milky, nutritive substance. In a few weeks the worm develops and, bursting the wall of its prison, makes its escape. * 61. Distribution. — The earthworms and their allies are found widely distributed throughout the world, and all exhibit many of the characters just described. The greatest differences arise in their mode of life : some are truly earthworms, but others are fitted for a purely aquatic existence in fresh water or along the seacoa
. Animal forms; a second book of zoology. Zoology. THE WOKMS 59 gether by elastic bands. A sac, the cocoon, is thus pro- duced, containing the eggs and a milky, nutritive substance. In a few weeks the worm develops and, bursting the wall of its prison, makes its escape. * 61. Distribution. — The earthworms and their allies are found widely distributed throughout the world, and all exhibit many of the characters just described. The greatest differences arise in their mode of life : some are truly earthworms, but others are fitted for a purely aquatic existence in fresh water or along the seacoast; a few have taken up abodes in various ani- mals and plants, and in some of these situations they extend far up the sides of the higher mountains. In all, the head is relatively indistinct, the number of bristles 011 each segment Fig. marine worm (Nereis). A ap- ° pearance at breeding season, and B, few, and for this and other at ()ther times. reasons all are included in the subclass Oligochaete, or " few-bristle " worms. 62. Nereis and its allies.—In many of the above-men- tioned situations members of a more extensive group of worms are found, with highly developed heads and many bristles arranged along the sides of the body. These are the Polychsetes or " many-bristle " worms, and as a repre- sentative we may take Nereis (Fig. 36), a very common. 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 Jordan, David Starr, 1851-1931; Heath, Harold, 1868- [from old catalog] joint author. New York, D. Appleton and company
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1902
