Parasites that live within host tissues do not have any direct need for attachment, but they often exhibit other morphological adaptations, usually in some aspect of body shape, that allow them to live there.
Many tissue parasites are unusually slender.
Capillaria lives entirely within the intestinal mucosa and its entire boy is thread-like.
Trichuris inserts its slender stichosome into the mucosa, but its stouter hind-body is free in the intestinal lumen.
Wehrdikmansia, like most of the filarid worms, lives in tissues outside the digestive system and is also long and slender.
Other tissue parasites have unusually stout bodies, not at all like their more "aerodynamically" shaped relatives that live in the intestinal lumen. Collriclum, for instance, is a trematode that lives subcutaneously in the throat of birds. It is almost spherical, unlike the typical flattened shape of most platyhelminths.
