Abstract
Coslenchus costatus and C. japonicus sp. n. were described and illustrated from Japan. Infra-specific variations of four Japanese populations of C. costatus were discussed comparing with the description of the species by ANDRASSY and showed that there found no differences strict enough to recognize them as being independent from the C. costatus, while a few characters within the description of the species were altered based on the Japanese specimens. C. japonicus sp. n. was related to C. franklinae in having a few head annules, head continuous to body contour, much reduced postuterine sac, however, it was readily distinguished from the latter by having 18 to 21 longitudinal ridges, slightly spaced opening of dorsal oesophageal gland from spear base, generally pre-vulval phasmids, and fewer body annules. Jpn. J. Nematol. 14: 28-39 (1984).
