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Because of their sessile lifestyle and the lack of the sensory and feeding structures usually associated with the cephalic end, fixing the antero-posterior (AP) polarity of tapeworms is somewhat equivocal and has been a matter of century-long debates. Koziol et al. offer the first molecular evidence finally fixing the scolex as the animal's anterior pole.
Minelli, A. (2016, March 10). The tapeworm’s elusive antero-posterior polarity. BMC Biology. BioMed Central Ltd. https://doi.org/10.1186/s12915-016-0244-7