This photo shows the size dimorphism that is typical of acanthocephalans, with the male (M) often being quite small compared to the female (F). These parasites are 15-25 mm long. In both specimens note the fully everted proboscis, with its rectangular shape and many rows of small hooks. Note that the neck of the proboscis is withdrawn slightly into the body. The proboscis receptacle is long, almost half the length of the body. The lemnisci, best seen in the male, are shorter than the proboscis receptacle. At the tip of the proboscis receptacle, proboscis retractor muscles attach and connect to the body wall. No giant nuclei are present in the body wall.
In the male, the two testes are small an located just above the tip of the proboscis receptacle. Five of the six cement glands are visible as small dark red spheres just posterior to the testes. This is an immature male; when mature the testes and cement glands would be about twice their present size.
Many eggs in various stages of development are visible as elongate bodies in the female specimen.