A new species of Strongyliid round worm - Trachypharynx natalensis - from the large intestine of the cane rat, is described. A new subfamily - Trachypharynginae - of the Strongylidae is created. New subfamilies of the Strongylidae are also created, viz. Gyalocephalinae, for the genus Gyalocephalus Looss, and Colobostrongylinae for the genus Colobostrongylus Sandground. The chief characteristics of these new subfamilies are given.