In a previous paper (1931) the writer described the presence of a spicule in the male of Capillaria [Hepaticola] hepatica, and gave reasons for believing that the apparent presence or absence of a spicule in the males of forms closely related to it is not a reliable taxonomic character. It was suggested that the genus Eucoleus Dujardin, which, like Hepaticola Hall, was based mainly on the supposed absence of a spicule, should likewise be suppressed as a synonym of Capillaria. Teixeira de Freitas & Lent (1935, 1936), in accepting this view, have drawn attention to an observation recorded by Creplin (1849), which had been generally overlooked, to the effect that a spicule is present in the genotype of Eucoleus (Trichosomum aërophilum Crepl., in Ersch & Gruber, 1839). Up to the present Creplin's observation has not, so far as the writer is aware, been confirmed. Some specimens of Capillaria aërophila from the lungs of silver foxes were recently received from Mr C. V. Watkins, M.R.C.V.S., who had noticed in a living male specimen what appeared to be a spicule projecting from the everted spicule-sheath, and enclosed a sketch of it in his letter. On examining the preserved material, the writer was able to confirm this interesting observation. In the specimen referred to by Mr Watkins, and in another individual, a very delicate structure, apparently a spicule, was seen projecting for a short distance beyond the end of the partly everted sheath.