. Zoology. Zoology. EARTH-WORMS. 51 swell out, and thus push the earth away on all sides, while it also swallows the dirt, which passes tlirough the digestive canal. In this way it may descend from three to eight feet in the soil. While earth-worms are in the main beneficial, from their habit of boring in the soil of gardens and ploughed lands, bringing the subsoil to the surface and allowing the air to get to the roots of plants, they occasionally injure young seedling cabbage, lettuce, beets, etc., drawing them during the night into their holes, or uprooting them.* Earth-worms lay their eggs
. Zoology. Zoology. EARTH-WORMS. 51 swell out, and thus push the earth away on all sides, while it also swallows the dirt, which passes tlirough the digestive canal. In this way it may descend from three to eight feet in the soil. While earth-worms are in the main beneficial, from their habit of boring in the soil of gardens and ploughed lands, bringing the subsoil to the surface and allowing the air to get to the roots of plants, they occasionally injure young seedling cabbage, lettuce, beets, etc., drawing them during the night into their holes, or uprooting them.* Earth-worms lay their eggs in June and July, at Fig. S4.—Earth-worms, nat. size, a, embryo (blastula) soon after segmentation of theyolli; 6, embryo further advancer!; o, mouth; c, embryo still older; fc, primitive streak; d, neurula;o, its mouth. The eggs of the European Lnmhrims rnlelhis are laid in dung, a single egg in a capsule; L. agricola lays numerous egg-capsules, each containing sometimes as many as fifty eggs, though only three or four live to develop. The de- velopment of the earth-worm is like that of the leech, the germ passing though a number of stages, the worm, when hatching, resembling the parent, except that the body is shorter and with a much less number of segments. The sea-worms have larger, more distinct bristles, as in Clymenella (Fig. 55), which livps in tubes in soft mud. *Darwin's Formatiou of vegetable mould through the action of 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 Packard, A. S. (Alpheus Spring), 1839-1905. N. Y. , Holt
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1897
