XXIII.— A Review of Recent Work on the Permian Non-Marine Lamellibranchs and its Bearing on the Affinities of certain Non-Marine Genera of the Upper Palaeozoic

PART I: THE FAUNAS. 1. Introduction. In the years immediately preceding the present war much new work was done on the Permian non-marine lamellibranchs in various regions, which has special significance by reason of the problems it presents to workers on the corresponding fossils of the Upper Carboniferous. The present review attempts to summarise the results of this work, to examine it critically and generally to bring the problems it raises into focus. It is not surprising that most of the recent researches which form the subject of this review have been carried out in the U.S.S.R., in view of the intensive exploitation of the Permian coals of the Siberian Basins. Unfortunately some of the literature is not easily accessible and in spite of the courtesy of the Soviet Embassy and Sir E. John Russell, Adviser to the Soviet Relations Branch of the Ministry of Information, the writer has failed to obtain copies of the various papers of Ragozin on the fauna of the Kuznetsk Basin. The difficulty at present is doubtless due to war conditions, but according to the bibliographies in Fedotov (1937 and 1938) Ragozin’s papers on this subject were published between 1931 and 1935 and copies of some have not been received by the principal British scientific libraries. The new genera proposed by Ragozin are recorded in “Nomenclator Zoologicus” and the “Zoological Record” (for 1935 and 1938) and doubtless at least one copy of each of the relevant papers was available in England, but Dr. L. R. This 250-word extract was created in the absence of an abstract In addition to the acknowledgments made in the Introduction and elsewhere I wish to thank my colleagues, Professor Trueman, Dr. Leitch and Dr. Eagar, for reading the typescript and discussing with me some of the problems raised. I also have to thank Dr. Eagar for the drawings reproduced in Figures 1 and 2, and the Geological Survey (Scottish Office) for the loan of specimens. I wish further to express my thanks to the Carnegie Trust for the Universities of Scotland for a grant towards defraying the cost of illustrations.