The animal parasites of sheep by unknow

Author:unknow
Language: eng
Format: epub
Tags: Sheep
Publisher: Washington, Gov't print. off.
Published: 1890-03-25T05:00:00+00:00

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T^NiA FiMBEiATA, Diesing.

Plate XIII.—DiesiDg's origiDal figures.

Fig. 1. Adult, natural size.

Fig. '2. Head, side view.

Fig. 3. Head, top view.

Fig. 4. Segments near head.

Fig. 5. Segments further removed from head.

Fig. 6. Some still more remote.

Fig. 7. From near end.

PLATE XIII

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TAENIA FIMBRIATA.

THE BROAD TAPE-WORM OF SHEEP.

T^NIA BXPANSA, Rud. Plates XIV and XV.

Tamia expansa^ the Broad Tape-worm, is one of the best known of the internal parasites of sheep, becaase of its flatness, length, and large size. In summer and fall it is quite abundant. The amount of pecuniary losses occasioned by its ravages depend upon the season and its abundance in affected flocks. It was introduced into tiiis country from Europe along with the imported flocks which harbored it. Since then it has been parasitical on our flocks from generation to generation. It is now distributed from the wooded hillsides of New England to the grazing lands of Georgia, over the fertile prairies of Ohio, Illinois, Iowa, and Nebraska, and the boundless prairies, basins, and mesas of Colorado, Utah, California, and Oregon 5 in short, over every sheep-grazing locality in the United States. Reported outbreaks from this vast extent of country are comparativdy few and scattered, but are sufficient to warn us that when the pastures become narrowed, older, and overstocked, we may expect the same trouble with this and other parasites as has been experienced by sheep raisers through all time in the more densely populated districts of other countries.

Description. —^The entire worm measures in length about 5 yards, and in width from one-twenty-flfth of an inch at the head to a half or three-quarters of an inch at the tail. Its thickness is from one-tenth to one-twelfth of an inch. These dimensions vary greatly, depending on the contracted condition of the worm when measured and on its state of preservation. Adult specimens taken from sheep may average less than 4 yards, or may slightly exceed 5 3 but they never, in this country at least, attain that gigantic measurement of 100 feet ascribed to them by European observers. The head is somewhat larger than the neck, and measures one-twenty-fifth of an inch in width. It is smooth on the end and has its four suckers directed anteriorly. Its neck, or that portion of the worm immediately succeeding the head, which is unsegmented, is shortor lacking. The body of the worm is apparently made up of a series of very short but extremely wide joints, which vary in length and width iu the successive portions of the body. The first rings of the tcenid are^ very short and narrow; the others are longer, but are always broader than long. Those segments which are about two-thirds the entire length 23038 A P 8 U3

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from the head are the longest. From these to the end they become gradually shorter and wider. In width the segments gradually increase from the head to the end. When first collected the texture of the worms is usually opaque

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