Cattiena fansipanis n. sp. (Nematoda: Rhigonematida: Carnoyidae) from a millipede (Myriapoda: Diplopoda: Spirobolida) in North Vietnam.

A new species of Cattiena Hunt & Spiridonov, 2001 from a diplopod (Spirobolida: Pseudospirobolellidae Brolemann) collected near Sa Pa, Lao Cai Province, Vietnam, is described. Females of Cattiena fansipanis n. sp. are closely related to females of two other known species of the genus, C. trachelomegali Hunt & Spiridonov, 2001 and C. trigoniuli Hunt & Spiridonov, 2001, but can be distinguished by the distinctly more anterior position of the vulva, abrupt constriction of the body at the vulval level, presence of two swollen portions of the oviducts, and longer body and tail. Males of new species differ by having a rounded cephalic region followed by 13-14 annules which are larger than those which follow them, a different size and shape of the spicules and gubernaculum, and body and tail length. Three size groups of juveniles were found in the host gut lumen, presumably representing second, third and fourth juvenile stages. The morphology of the juvenile stages is described.

Aulacnema monodelphis n. g., n. sp. and Angiostoma coloaense n. sp. (Nematoda: Rhabditida: Angiostomatidae) from terrestrial molluscs of Vietnam.

Two species of nematodes, Angiostoma coloaense n. sp. and Aulacnema monodelphis n. g., n. sp. (Angiostomatidae: Rhabditida) are described from terrestrial molluscs of Vietnam. Both species are characterised by a long bowl-shaped buccal cavity and typically angiostomatid male bursal alae, spicules and gubernaculum. The new genus, Aulacnema n. g., is erected for the first reported monodelphic angiostomatid. Angiostoma coloaense n. sp. can be distinguished from other species of Angiostoma Dujardin, 1845 by having a buccal cavity length greater than its width and the absence of tail spikes on both males and females.