(Uploaded by Plazi for the Bat Literature Project) Physaloptera brevivaginata Seurat, 1917 (Nematoda: Physalopteridae) is redescribed. Seurat's (1917) original description of this species was based on a single immature female. Detailed morphological study of several males, mature and, above all, immature females from the stomach of the lesser mouse-eared bat Myotis blythii (Tomes) (Chiroptera: Vespertilionidae) in Spain, has elucidated many new morphological characters. This physalopterid, species is distinguished from other closely-related species by the lengths of the body and spicules, the equatorial position of the vulva, the morphology of the female reproductive system and by a small conical process on the tail of mature females. M. blythii is a new host for this nematode.