Morphology of Proteocephalus

(Redrawn after LaRue 1914)

The presence of four suckers on the scolex is common for this genus, but the apical papilla is present only in some species. The reproductive system is similar to the scheme of the Cyclophyllidea, except that the vitellaria are follicular and occur in two lateral fields. A feature that is difficult to see except in cross-section is that the testes may be located more externally in some species ("cortical") and deeper ("medullary") in others.