Reproduction in the shallow-water, sponge-dwelling, branching syllid Ramisyllis multicaudata exhibits several features unique among syllids and among annelids in general. We describe and illustrate the segmental asymmetry which intervenes between regions of symmetry, only found in branching annelids. We describe the morphology of the stolons and of the stolon stalks, which are unique to branching syllids but differ in detail from those of the other known branching syllid, Syllis ramosa. We also illustrate newly found paddle-shaped chaetae, which might indicate that these stolons do swim. We list the number of branch points and termini in an effort to gauge the extent of branching in a worm contained in a small sponge. The species appears to have separate sexes, but this cannot be proven. We compare R. multicaudata and S. ramosa as originally described and find new morphological differences between the branching syllid from Japan described as S. ramosa and R. multicaudata. We also compare the known stolons of branching syllids to those of other genera of the ‘ribbon clade’, a group including Trypanobia and Trypanosyllis, now known to be close relatives of R. multicaudata. Ramisyllis multicaudata is the first member of the ribbon clade, and one of few Syllinae, known to have sexually dimorphic stolons.

This study was performed in order to define Schistosoma mansoni antigens that are able to function as modulator agents in the granulomatous hypersensitivity to parasite eggs in BALB/c and C57BL/6 mice. A fraction of S. mansoni, designated PIII, derived from adult worm antigen preparation (SWAP) was obtained using anion-exchange chromatography on an FPLC system. Immunization of mice with PIII in the presence of Corynebacterium parvum and Al(OH)3 as adjuvant induced an immune response in these animals as determined by ELISA and spleen cell proliferation assays against S. mansoni antigens SEA, SWAP and PIII. In addition, PIII caused a significant degree of protection against a challenge infection in immunized mice as observed by the decrease on worm burden recovered from the portal system. We also showed that PIII profoundly inhibited the vigorous anamnestic granulomatous response to eggs in the liver and lungs. This suppression correlated with a significant decrease in granuloma size. From these results we conclude that the PIII preparation contains antigens that can mediate protective anti-parasite immunity and downregulate granulomatous hypersensitivity to S. mansoni eggs.

A unique specimen of an unusual elongate segmented compression fossil, Polylurida aenigmatica n. gen., n. sp., is described and illustrated. The bilaterally-symmetrical, dorsoventral structure (c. 6·5 cm long × 0·8 cm maximum width) narrows towards both ends and is subdivided into approximately 19 similar tapering segments, showing no evidence of tagmosis, appendages or an internal gut. The segments are covered with a substantial papillose organic cuticle, each segment bearing towards one end a pair of transverse calcareous bars. These bars are perforated by simple canals filled with strands of dark organic material which traverse their whole thickness and flare out superficially to form pores on both their lower and upper surfaces. Internal horizontal lamination of the bar material suggests an episodic accretionary pattern of skeletal growth. The bars appear to represent internal skeletal structures and are restricted to one side (dorsal or ventral) of the body, where the adjacent cuticle is locally thickened to form a corresponding series of discrete paired densely papillose transverse bands. Although Polyurida may be an unusual segmented worm, its singular suite of characters and lack of data prevent assignment to any higher taxon.