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The ultrastructure of the pseudocnidae (filament‐core rhabdoids) of the palaeonemerteans Cephalothrix cf. rufifrons and Carinomella lactea is described and the phylogenetic utility of these organelles evaluated. Pseudocnidae of Cephalothrix cf. rufifrons are clavate structures, measuring 3–5 µm in length with a bulbous lateral process present near their midregion, whereas those of Carinomella lactea are rod‐shaped structures, measuring 2–3 µm in length and lack a lateral process. In both species, these structures exhibit a somewhat electron‐lucent cortex, an electron‐dense medulla and a distinct filament‐like core, extending from the apex of the pseudocnida toward its base. The pseudocnidae are situated within pseudocnida‐forming cells that constitute a portion of the glandular proboscis epithelium and are oriented parallel to the apical basal axis of the cell. No evidence of core extrusion was observed in these species. Comparative structural analyses confirm that these secretory granules are neither rhabdite homologues nor cleptocnidae. Position and ultrastructure of palaeonemertan pseudocnidae support the hypothesis that they are homologous to those of heteronemerteans, and pseudocnidae are interpreted as a provisional synapomorphy of the Anopla, as suggested in previous studies. However, recent molecular phylogenies of nemerteans do not support anoplan monophyly, necessitating alternative interpretations of pseudocnida evolution, namely, that these structures were present in the nemertean common ancestor and subsequently lost in the hoplonemerteans and Carinoma or that they evolved independently in the Pilidiophora and a Cephalothricidae + Tubulanidae clade. A rigorous explanation of pseudocnida evolution awaits a simultaneous analysis of molecular and morphological characters inclusive of pseudocnidae. [ABSTRACT FROM AUTHOR]

Frontonemertes serpentina, Satellitenemertes satellitensis and Sanjuannemertes willowsi new genera and species are described as three members of the order Hoplonemertea, suborder Monostilifera. In general morphology, F. serpentina is most similar to Nemertes rubrolineata in having the two layers of the body wall longitudinal musculature, no pre‐cerebral septum and retractor muscles originating in the outer longitudinal muscle layer in the cephalic region {Chernyshev (1992) proposed a new genus, Tetranemertes , for Nemertes [type species, N. antonina Quatrefages, 1846]}. Satellitenemertes satellitensis appears to be most closely related to members of the genus Amphiporus . Sanjuannemertes willowsi has a common atrium for the proboscis pore and mouth, as in some polystiliferous hoplonemerteans. The original description of Nipponnemertes bimaculata (Coe 1901) is supplemented on the basis of re‐observation of its features. The significant characters are explained and discussed. [ABSTRACT FROM AUTHOR]

Specimens of Tubulanus riceae new species (Nemertea: Palaeonemertea) were collected from a Phragmatopoma worm reef in the surf zone at Fort Pierce (Florida, USA) and from sublittoral rubble at Carrie Bow Cay (Belize) and Bocas del Toro (Panama). They have well‐developed lateral sensory organs, form a cellophane‐like tube and appear to have ocelli‐like structures. The latter, if confirmed as ocelli, would be the first reported for a tubulanid. The new species is characterized by a unique color pattern, resembling that of Tubulanus rhabdotus , but it is distinctive in its milky‐tan ground color with annular bands of brown pigment bounded by white margins and in having up to six to eight dorsal, longitudinal, but broken, reflective white stripes. [ABSTRACT FROM AUTHOR]

Yin and Zeng (Marine Science Bulletin 1984;3:51–58; Oceanologia et Limnologia Sinica 1985;16:323–335; Journal of Shandong College of Oceanology 1986;16:1–9; Marine Science Bulletin 1988;1:176–187) described two new genera and three new species of heteronemerteans with a branched proboscis, Dendrorhynchus zhanjiangensis Yin & Zeng, 1984, Dendrorhynchus sinensis Yin & Zeng, 1985 and Polydendrorhynchus papillaris Yin & Zeng, 1986. All three species were described from specimens collected at the same locality—Xiashan Beach Park, Zhanjiang, China. Additional specimens have been collected from nearby sites during recent years. Observations on these additional specimens and re‐examination of the type specimens suggest that all three species should be synonymized under the single taxon, Dendrorhynchus zhanjiangensis Yin & Zeng, 1984. [ABSTRACT FROM AUTHOR]