The hosts of the species, which generally infect the coelom of their hosts, in Monocystidae family are usually oligochetes (a subclass of animals in the phylum Annelida).
The hosts of the species in this family are usually oligochetes. The species in this family generally infect the coelom of their hosts. Oligochaeta (/lkit, -o-/) is a subclass of animals in the phylum Annelida, which is made up of many types of aquatic and terrestrial worms, including all of the various earthworms. The Monocystidae are a family of parasitic alveolates in the phylum Apicomplexa. 
