_The treatment is preventive_. Drainage water from a pasture infested with snails harboring immature flukes is a source of infection, and should not be used as a water supply for cattle and sheep. In sections where the disease is prevalent, sheep should not be pastured on low, poorly-drained land. Such land should be used for pasturing horses and cattle, but if possible, it should be first drained and cultivated. Careful feeding and good care may help the affected animals to recover. [Illustration: FIG. 73.--Tapeworm larvae in the peritoneum (_Cysticercus cellulosa_).] TAPEWORMS OR CESTOIDES.--Tapeworms are formed by a chain of segments, joined together at their ends, and are flat or ribbon-shaped (Fig. 71). The head segment is small, and possesses either hooks or suckers. It is by these that the worm attaches itself to the lining membrane of the intestine. The anterior segments are smaller and less mature than the posterior segments. Each segment is sexually complete, possessing both the male and female organs, and when mature, one or more of them break off and are passed out with the faeces. The mature or ripe segments are filled with ova. On reaching the digestive tract of a proper host, usually with the drinking water or fodder, the embryo is freed from the egg. The _armed embryo_ uses its hooklets in boring its way through the wall of the intestine. It then wanders through the tissues of its host until it finally reaches a suitable place for development (Figs. 71 and 73). On coming to rest, it develops into the larva or bladder-worm, which when eaten by a proper host gives rise to the mature tapeworm. The following tables give the most important tapeworms: ADULT FORMS Name Host Organ Taenia expansa Sheep and ox Intestine Taenia fimbriata Sheep Liver Taenia denticulata Cattle Intestine Taenia alba Cattle Intestine Taenia perfoliata Solipeds Intestine Taenia mamillana Solipeds Intestine Taenia echinococcus Dog Intestine LARVAL FORMS Name Host Cysticercus bovis Cattle Cysticercus cellulosa Swine and man Cysticercus tennicollis Cattle, sheep and swine Coenurus cerebralis Cattle and sheep Echinococcus polymorphus Cattle, sheep, swine and man The adult tapeworms _Taeniae saginata_ and _soleum_, of which the _Cysticerci bovis_ and _cellulosa_ are the larvae forms, occur in man. The larvae are present in meat and pork, and this form of parasitism is termed beef measles in cattle and pork measles in hogs. Man becomes host for these two forms of tapeworms through eating measly pork or beef that is not properly cooked.