Metascolex

In Cestodes , The posterior portion of a divided Scolex . Consists of folds of tissue generally encircling or hiding the Suckers .

It either originates from the base of  scolex  , sometimes forming a sort of Collar , or from Folds of tissue between the Suckers   (Khalil , L.F.et al. , 1994)

e.g. Amphoteromorphus in South American Siluroid fishes