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Hubrechtella ijimai is reported for the first time from South Korea (East China Sea) and China (Yellow Sea), about 260 and 930 km from the nearest locality in Japan. Additional morphological data, confocal laser scanning microphotographs, and DNA data (COI sequences) are provided. This species possesses high intraspecific genetic COI p-distances for nemerteans (1.6–6.3%).

A selection of pilidium larvae are described from plankton collected from Bamfield Inlet in British Columbia, Canada, the Florida Gulf Coast and the Great Barrier Reef of Australia. Among the Bamfield larvae are examples attributable to Cerebratulus and Lineus, the former being among the largest pilidia known, up to 1.45 mm in height, and two previously undescribed types. Pilidium brachiatum from Florida is re-described to highlight differences from Hubrechtella larvae, which are superficially similar, and an assortment of tropical forms is included to illustrate the predominance of the compressed gyrans-type larva in this location. Pilidium larvae have typically been categorized by their shape as seen in lateral view. This account emphasizes the importance of three-dimensional shape, pigmentation, overall architecture and behaviour in distinguishing between the larvae of different species.

The paper includes a description of Hubrechtella juliae sp. nov. from Peter the Great Bay. Based on the paraphyly of the family Hubrechtiidae s.l., we propose to combine the genera Hubrechtella, Tetramys, and Coelia into the family Hubrechtellidae fam. nov.

One new genus and six new species of palaeonemerteans are described and illustrated from Hong Kong and the New Territories; these areHubrechtella sinimarinussp. nov. andParahubrechtia jillaegen. etsp. nov.in the Hubrechtidae, andCallinera bergendalisp. nov.,Carinina sinensissp. nov.,Tubulanus hylbomisp. nov.andTubulanus longivasculussp. nov. in the Tubulanidae. These bring the known number of palaeonemertean species from Hong Kong to 11; a key to these species, based primarily upon features distinguishable in the living animals, is provided.

Riserius pugetensis gen. n., sp. n. is described from the northwest coast of Washington, U.S.A. It is probably a heteronemertine and, as such, would be the first known mesopsammic member of that order; it lives in the interstices of medium to coarse, moderately clean sands. Its morphology presents some attributes considered characteristic of mesopsammic fauna. The effect of some of these attributes is a generalized appearance of anatomical ‘simplicity’ and, as with other mesopsammic metazoans, this presents difficulties in distinguishing between primitiveness and reduction. In the new species such problematic features include the lack of subepidermal glandular cells and connective tissue, reduced proboscideal musculature, simple blood-vascular system, and the presence of a ‘secondary’, outer circular musculature in the body wall. The general appearance of this new species is very similar to the so-called palaeonemertine Hubrechtella and characteristics of both suggest relationship with the baseodiscid heteronemertines. These relationships are explored in light of a modified interpretation of proboscideal musculature, a traditional cornerstone of heteronemertinean taxonomy.

Two new palaeonemerteans, Carinoma patriciaesp. nov., and Hubrechtella queenslandicasp. nov., from the Great Barrier Reef province of Australia, are described and illustrated. The systematic relationships of these nemerteans are discussed and emended diagnoses are given for the genera Carinoma (Carinomidae) and Hubrechtella (Hubrechtidae).