St.-Pétersbourg, Eggers & Cie., [1863]-1864. Large 4to (32.5 x 24.3 cm). 38 pp.; four finely lithographed plates. Original printed wrappers.

A rare and important contribution to Palaeozoic (Upper Devonian) invertebrates (chiefly brachiopods and molluscs, e.g., Nucula, Pecten, Chemnitzia), including descriptions and illustrations of new species. Published in the Bulletin of the Académie impériale des Sciences de St.-Petersbourg Volume 7(3), together with a few smaller papers. Written by the Russian geologist and palaeontologist Pyotr Petrovich Sémionof (as on the wrapper)or Semenov (as in the paper itself) or Semyonov (1827-1914) and his colleague, Valerian von Möller, or Meller (1840-1910). Uncut. Wrapper edges a bit frayed, spine cover chipped; some light foxing, and marginal damp-staining (Sémionof and Möller's paper least affected); otherwise, very good.