Gnathostomulida
Name Meaning: Jaw orifice
English Common Name: Jaw worms
Major distinguishing characteristics:
Approximate number of species described: about 300
Natural History
Jaw worms are all aquatic and marine. They live in the sand and mud in shallow coastal waters.
Taxonomy
There are two recognized orders within the Phylum Gnathostomulida.
Filospermoidea
Bursovaginoidea
Anatomy
The powerfully jawed mouth is just behind the head end and opens into a blind-ending tube. There is no anus. They have no circulatory or respiratory system.
They are hermaphroditic, with one ovary and two testes.