Belondiridae. Neck tapering uniformly to the narrow rounded
lip region which is not set off in any manner. Tails of both sexes
filiform. Supplements consisting of an adanal pair and a numerous
ventromedian ones. Submedian papillae present. Spear length
about equal to lip regon width in both known species, the aperture occupying
less than one-half of its length. Esophagus enlarged near middle
by gradual expansion the basal portion surrounded by a sheath of
broad spiral nuscles. Ovaries one or two. Male prerectum extending
anterior to supplement series. Lateral cords usually about one-sixth
as wide as body, the lateral pores apparently in two lines.
Type species: Oxydirus oxycephaloides (DeMan, 1921)
Diagnosis: Belondiridae with the above general description.
The long slender tails of both sexes immediately distinguish it from all
other Belondiridae except Swangeria from which it is differentiated
by the structure of the pharynx and the form of the esophagus.
(Description- Thorne, 1939).
Specimens from Costa Rica