The protozoan genus Pyxicola Kent, 1881 (Ciliata, Peritrichida, Vaginicolidae) has been critically revised. It is now considered to include the nominal genera Pachytrocha and Caulicola. An annotated list of the hitherto described nominal species is given. Eight species and two formae are recognized within the genus. A short description of each of these and a key to their identification are given. All recognized species are figured; many illustrations from the literature have been redrawn and brought together to facilitate comparison and to justify the taxonomical decisions which have been taken.