This order is characterized by the presence of lateral longitudinal lacunar canals and a double-walled proboscis receptacle. The nuclei of the hypodermis (outer layer of skin) are fragmented and the males have two to seven cement glands, unlike their relatives the Archiacanthocephala, which always have eight.
Characterized by lateral longitudinal lacunar canals and a double-walled proboscis receptacle, this order is also marked by fragmented nuclei of the outer skin layer and distinct numbers of cement glands in males, differing from their relatives the Archiacanthocephala, which consistently possess eight.