Gravid females of the little-known nematode species Philometra rubra ( Leidy, 1856 ) (Philometridae) are described from specimens from the abdominal cavity of the striped bass, Morone saxatilis (Walbaum), in South Carolina and Canada. The specimens were studied with the use of light and scanning electron microscopy. This species is mainly characterized by the distribution and different sizes of cephalic papillae from the external circle, which is a unique feature compared to other philometrids. Other characteristic features are the shape of the posterior end of body, size and location of caudal projections, and the presence of a well-developed anterior esophageal inflation. The morphology of the male of P. rubra and the life cycle of this nematode are still unknown.