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Greek: kestos = band, belt.
Class of Platyhelminthes.
All members of the class Cestoidea live as parasites, are extremely dorsoventrally flattened, may reach a length of several meters in some species and thus are called tapeworms. In general, the adults inhabit the intestines of their hosts, being anchored to the intestinal wall by means of type-specific holdfast organs (Fig. 1). Their principal body organization corresponds to that of trematodes with the exception of the lack of an intestine; thus all nutrients have to be taken up through the syncytial tegument ( Figs. 1, 3– 5). The ontogenesis of the cestoda proceeds in most species as metamorphosis employing different larval stages (Fig. 2). In relatively rare cases (e.g., Echinococcus spp.; Fig. 2), an alternation of different generations is involved in the life cycle; however, all tapeworm need an alternation of hosts (see Eucestoda/Table 1). The classification of the...
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