Seven new species of limpets from hydrothermal vents are described in five new genera in the new family Peltospiridae (new superfamily Peltospiracea). Limpets in this family are known only from the hydrothermal vent community at two sites, near 21°N and 13°N, on the East Pacific Rise. New genera and species are: Peltospira, type species P. operculuta from both sites, and P. delicata from 13°N; Nodopelta, type species N. heminoda from both sites, and N. subnoda from 13°N; Rhynchopelta, type species R. concentrica from both sites; Echinopelta, type species E. fistulosa from 21°N; Hirtopelta, type specics H. hirta from 13°N. These limpets are associated with the Pompei worm Alvinella, except for Rhynchopelta, which is associated with the vestimentifcran worm Riftia.

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Six new species of limpets from hydrothermal vents at spreading centres, hydrothermal vents on seamounts, or cold sulphide seeps are described in three new genera in the new family Neolepetopsidae. Anatomy is detailed separately by V. Fretter (1990). The family is considered to be a living descendant of the Palaeozoic‐Mesozoic family Lepetopsidae (proposed herein), based on Lepetopsis Whitfield, 1882. Both families are placed in the new superfamily Lepetopsacea, new suborder Lepetopsina, order Patellogastropoda. New genera and species are: Neolepetopsis, type species N. gordensis, from the Gorda Ridge, and three additional species: N. densata, from an active sulphide chimney near 12°N on the East Pacific Rise, N. verruca from a sulphide chimney near 21° N on the East Pacific Rise, and N. occulla from hydrothermal vents on the caldera floor of Green Seamount near 21° N; Eulepetopsis, type species E. vitrea, from hydrothermal vents at the Galapagos Rift and the East Pacific Rise near 21°, 13°and 11°N; Paralepetopsis, type species P. floridensis, from cool, hypersaline, sulphide seeps at the base of the continental slope off the west coast of Florida. Inclusion in Patellogastropoda is indicated by plesiomorphic characters: symmetrical shell lacking coiled phase, no epipodium in adult, single dorsally arched jaw, docoglossate dentition with a licker below the tip of the radula, both left and right kidney, and gonad discharging through right kidney. The radula differs from that of other patellogastropods in having the denticle caps delicate and non‐mineralized, the shafts articulating with shafts and cusps of adjacent teeth in the row and with those in adjacent rows, and in having some capacity for longitudinal bending. The rachidian is well developed; the first two pairs of lateral teeth are regarded as homologues of the inner lateral teeth of Patella; the third lateral tooth is larger than the others and is considered a modified pluricuspid tooth; there are two pairs of plate‐like marginals. Tooth morphology differs in each genus but all have a very long second lateral with a strong mid‐shaft nub to articulate with the overhanging edge of the pluricuspid. The neolepetopsid radula is interpreted as close to that of the patellogastropod archetype except for its lack of mineralization and reduction in the number of marginal teeth. The radula in living docoglossate outgroups (chitons and monoplacophorans) is mineralized and the teeth are articulating. Articulating teeth are therefore regarded as plesiomorphic in patellogastropods. I speculate that articulating teeth may have been characteristic of Palaeozoic and early Mesozoic patellogastropods and that the non‐articulating, straight‐shafted and rapidly replaced teeth of extant Patellina may have arisen in the Mesozoic, a time at which patellogastropods of modern appearance underwent a radiation in shallow‐water habitats.

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McLean, J. H. 1995. Anatomy and systematics of bathyphytophilid limpets (Mollusca, Archacogastropoda) from the northeastern Pacific.-Zool. Scr. 2.5: 35-49,Bathyphytophilus diegensis sp. n. is described on basis of shell and radula characters. The radula of another species of Bathyphytophilus is illustrated, but the species is not dcscribcd since the shell is unknown. Both species feed on detached blades of the surfgrass Phyllospadix cdrricd by turbidity currents into continental slope depths in the San Diego Trough. Thc anatomy of H. diegensis was investigated by means of semithin serial sectioning and graphic reconstruction. 'The shell is limpctlike; the protoconch resembles that of pseudococculinids and other lepctclloids. The radula is a distinctivc, highly modified rhipidoglossate type with close similarities to the lcpctellid radula. Thc anatomy falls well into the lepetelloid bauplan and is in general similar to that of Pseudococculinidae and Pyropcltidae. Apomorphic features are the presence of gill-leaflets at both sidcs of thc pallial roof (shared with certain pseudococculinids), the lack of jaws, and in particular many enigmatic pouches (bacterial chambers?) which open into the postcrior oesophagus. Autapomorphic characters of shell, radula and anatomy confirm thc placement of Rathyphytophilus (with Aenigrnabonus) in a distinct family, Bathyphytophilidac Moskalev, 1978. As revealed by a cladistic study, the Bathyphytophilidae should be classified within the Ixpctclloidca closc to thc Lcpctcllidae, Pyropeltidae, and Pseudococculinidae. 0 1996 The Norwegian Academy o f Sciciicc and Letters.