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Populations of Atriplex canescens var. gigantea were found in Lamta, Bouficha-Enfidha (central Tunisia), and Medenine (southern Tunisia). Literature data concerning the presence of this species in Tunisia are contradictory but now our data confirm its occurrence in the country. On the other hand, this variety is reported in the present paper for the first time both in Tunisia and in North Africa in general. Morphological characters and ecological data are presented, as well as notes about patterns of infraspecific variability of A. canescens. Nomenclatural notes on infraspecific names in A. canescens, as well as on the closely related species A. garrettii, are provided. The types of the names A. canescens var. laciniata, A. canescens var. macilenta, A. garrettii, Obione occidentalis var. angustifolia, and Pterochiton occidentale, that in earlier publications were erroneously considered to be holotypes, are in fact lectotypes (for most of taxa) under Art. 9.10 of the ICN. Isolectotypes were found at CAS (A. canescens var. laciniata and A. canescens var. macilenta), GH (A. canescens var. macilenta), and YU (Atriplex nuttallii).

Three species of fossil polyplacophoran molluscs are known from Ireland. Two species were originally described in the nineteenth century: Helminthochiton grifftthi Salter in M'Coy, 1846 and Pterochiton thomondiensis (Baily, 1859), and an articulated specimen representing a third indeterminate species, described here for the first time. Previous work on the evolutionary context of these species has relied on published illustrations and descriptions without examination of the type material. As chitons are considered rare in the fossil record, these specimens represent an interesting and important aspect of Irish paleobiology.

Three important collections of European Devonian and Lower Carboniferous polyplacophorans have been located in United States institutions. The specimens provided a basis for better description of important characters and clarified some taxonomic assignments. Two new polyplacophoran species are in the collections, Helminthochiton carpenteri from the Devonian of Germany and Pterochiton absidatus from the Lower Carboniferous of Belgium. Beloplaxus sagittalis (Sandberger and Sandberger, 1853–1855) is recognized as a multiplacophoran and a new genus and species of turrilepadid, Bouturrilipas scutatus, is proposed.

Several hundred specimens of Pterochiton concinnus (Richardson) have now been collected from the Mazon Creek area. All are articulated, and most show all eight valves, held in place by a girdle, the margin of which is heavily spiculate. Most specimens preserve the radula, which is remarkably similar to that of living specimens.