In 1923, the writer in studying some species of the family Trichostrongylidæ, had occasion to create a new genus Graphidioides to receive the form previously known as Graphidium affine (Megnin, 1895), Railliet and Henry, 1909. This species differs from the type species of the genus Graphidium on the following points: absence of cervical papillæ, shape of bursa and disposition of ventro-ventral rays, shape of accessory piece and spicules, shape of the ovejectors and vagina and posterior extremity of the female. In an addendum on the remaining species of Graphidium, G. rudicaudatum the following statement was made:—

“Graphidium rudicaudatus R. & H., 1909, from Viscacia viscacia from Argentina resembles G. affinis very closely. It differs mainly by its smaller size, equal ovejectors, sharply pointed externo-dorsal ray and absence of an accessory piece. Its affinities to Graphidioides are so close, that the latter point requires re-investigation. The other points are only of specific value, and it is proposed to include it in this new genus. Should the absence of an accessory piece be confirmed, its position would require re-determination.”