. A textbook in general zoology. Zoology. FLATWORMS, ROUNDWORMS, AND ROTIFERS 05 -m. and usually taper to the posterior end. They have two eyes on the upper surface of the body at the anterior end. It is of the parasitic flatwornis that we wish especially to speak, namely, the flukeworm and tapeworm. Flukeworm.—This worm has a flattened, leaflike body (Fig. 29), from three fourths of an inch to two inches in length. It is parasitic in the livers of sheep and cattle, especially the former, and causes the dis- ease known as Ziver rot. It exists in this country, but is especially preva- lent in E
. A textbook in general zoology. Zoology. FLATWORMS, ROUNDWORMS, AND ROTIFERS 05 -m. and usually taper to the posterior end. They have two eyes on the upper surface of the body at the anterior end. It is of the parasitic flatwornis that we wish especially to speak, namely, the flukeworm and tapeworm. Flukeworm.—This worm has a flattened, leaflike body (Fig. 29), from three fourths of an inch to two inches in length. It is parasitic in the livers of sheep and cattle, especially the former, and causes the dis- ease known as Ziver rot. It exists in this country, but is especially preva- lent in England, and causes the loss of many sheep there annually. The adult worm has two suckers at the anterior end of the body for attachment to its host. While in the liver of the sheep the worm lays great numbers of eggs which find their way to the intestines of the host and thence to the outside world. If an egg falls on damp herbage or in water there hatches from it a minute, ciliated embryo (Fig. 30). This embryo swims about in the water until it finds a certain species of snail. It then actually bores its way into the body of the snail, and after undergoing compli- cated changes-transforms to an elongated body called a redia (Fig. 31). After a time, there are formed within the redia certain bodies called cercarice. Each cer- caria, which is provided with a long tail, eventually escapes from the redia and forces its way Fig. 29. — Civer flukewoiin; m, mouth; r, re- p r o du c t i ve opening; s, 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 Herrick, Glenn W. (Glenn Washington), 1870-1965. New York, Cincinnati [etc. ] American Book Company
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
