OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES No. 146, 71 pages. February 25, 1987 PALEOZOIC POLYPLACOPHORA: A CHECKLIST AND BIBLIOGRAPHY by Allyn G. Smith California Academy of Sciences, San Francisco, California 94118 LIBRARY and Richard D. Hoare I MAR 19 198? Department of Geology, Bowling Green State University, Bowling Green, Ohio 43403 I Woods Hole, Mass. »■■ »■»■>■ Abstract: An annotated checklist of 130 accepted species of Paleozoic polyplacophorans, as of 1985, is presented including complete synonymies, geological age, occurrences, location of specimens, and remarks. Reassignment within the classification is made, where possible, and a systematic arrangement is given. Fourteen species, based upon present information are indeterminate as to generic placement and 15 additional taxa, originally described as polyplacophorans, are here rejected. In addition, a list of 23 occurrences of unnamed specimens is included for completeness of known distribution. A bibliography of 193 citations contains all pertinent references to Paleozoic material included within the Class Polyplacophora, whether or not the taxonomic assignment is acceptable. Known Paleozoic polyplacophoran taxa are about equally distributed geographically between Great Britain, continental Europe, and North America. Stratigraphically, the largest number of described taxa are from Mississippian and Ordovician strata. Of the 153 named and unnamed taxa, 74 are Lower Paleozoic (Cambrian-Devonian) and 79 are Upper Paleozoic (Mississippian-Permian). New taxa proposed herein are: Acutichiton etheridgei n. sp., Lekiskochitonidae n. fam. Foreword Allyn G. Smith was in the process of compiling a comprehensive checklist and bibliography on Paleozoic polyplacophorans at the time of his death in August 1976. Smith's unfinished manu- script was forwarded to Ellis L. Yochelson, U.S. Geological Survey, Washington, D.C. upon his death. Yochelson asked R. D. Hoare, Depart- ment of Geology, Bowling Green State Univer- sity, Bowling Green, Ohio to prepare the manu- script for publication. The manuscript of the checklist and bibliog- raphy was submitted to the Editorial Board of the California Academy of Sciences essentially unchanged from the way it was left by Smith at the end of 1 975. At the board's request the manu- script was brought up to date, including known work in press, to make it a more useful contri- bution. Introductory remarks are modifications of those used by Smith (1973) for his Mesozoic checklist and bibliography. Compilations of age distributions, the revisions of systematic ar- rangement, and the presentation of a new sys- [i] OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES No. 146, 71 pages. February 25, 1987 PALEOZOIC POLYPLACOPHORA: A CHECKLIST AND BIBLIOGRAPHY by Allyn G. Smith California Academy of Sciences, San Francisco, California 94118 (LIBRARY MAR 19 1967 Department of Geology, Bowling Green State University, Bowling Green, Ohio 43403 J Woods Hole, Mass. mm Abstract: An annotated checklist of 130 accepted species of Paleozoic polyplacophorans, as of 1985, is presented including complete synonymies, geological age, occurrences, location of specimens, and remarks. Reassignment within the classification is made, where possible, and a systematic arrangement is given. Fourteen species, based upon present information are indeterminate as to generic placement and 15 additional taxa, originally described as polyplacophorans, are here rejected. In addition, a list of 23 occurrences of unnamed specimens is included for completeness of known distribution. A bibliography of 193 citations contains all pertinent references to Paleozoic material included within the Class Polyplacophora, whether or not the taxonomic assignment is acceptable. Known Paleozoic polyplacophoran taxa are about equally distributed geographically between Great Britain, continental Europe, and North America. Stratigraphically, the largest number of described taxa are from Mississippian and Ordovician strata. Of the 153 named and unnamed taxa, 74 are Lower Paleozoic (Cambrian-Devonian) and 79 are Upper Paleozoic (Mississippian-Permian). New taxa proposed herein are: Acutichiton etheridgei n. sp., Lekiskochitonidae n. fam. Foreword Allyn G. Smith was in the process of compiling a comprehensive checklist and bibliography on Paleozoic polyplacophorans at the time of his death in August 1976. Smith's unfinished manu- script was forwarded to Ellis L. Yochelson, U.S. Geological Survey, Washington, D.C. upon his death. Yochelson asked R. D. Hoare, Depart- ment of Geology, Bowling Green State Univer- sity, Bowling Green, Ohio to prepare the manu- script for publication. The manuscript of the checklist and bibliog- raphy was submitted to the Editorial Board of the California Academy of Sciences essentially unchanged from the way it was left by Smith at the end of 1 975. At the board's request the manu- script was brought up to date, including known work in press, to make it a more useful contri- bution. Introductory remarks are modifications of those used by Smith (1973) for his Mesozoic checklist and bibliography. Compilations of age distributions, the revisions of systematic ar- rangement, and the presentation of a new sys- [l] OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 tematic arrangement are based upon his remarks and upon work since his death. Introduction An exhaustive review of the literature relating to fossil Polyplacophora (chitons) was made in 1956-60 during the preparation of a synthesis of this class for the Treatise on Invertebrate Pa- leontology (Smith 1 960). The treatise format pre- cluded a listing of described fossil species, except type species, and space requirements permitted publication of only selected references. Thus, for the benefit of future studies, a list of the described species of fossil polyplacophorans was assembled in order to bring together all of the widely scat- tered information on the group. Species of other groups, initially considered to be polyplacoph- orans, were included. A checklist and bibliog- raphy of Mesozoic Polyplacophora taxa has been published (Smith 1973). The appended annotated checklist covers all published Paleozoic polyplacophoran occur- rences that have been located. All names covered in the literature have been included. The doubt- ful status of several so-called fossil polyplacoph- orans, the lack of an adequate number of spec- imens for other taxa, poorly preserved material, undoubted misidentifications, or a combination of these all present problems for future workers to resolve. The list is arranged alphabetically, by species, each name is followed by a complete synonymy, the geological horizon of occurrence, available data on the type locality and other lo- cations where the species is reported to have been collected, and the location of type and other iden- tified specimens, if known. Pertinent comments are added to the extent that these appear to be needed to provide useful information for a better understanding of the species. Because of space considerations, many original species descrip- tions have been omitted as these are available from the literature. For the sake of brevity several institutions which are repeated numerous times, especially under location of material, have been abbrevi- ated. These are: BGSU— Department of Geology, Bowling Green State University, Bowling Green. BM (N.H.)— Department of Geology, British Museum of Natural History, London. CAS — Geology Type Collection, California Academy of Sciences, San Francisco. MCZ— Museum of Comparative Zoology, Har- vard University, Cambridge. OSU— Orton Museum, Ohio State University, Columbus. OU— Fossil Invertebrate Repository, University of Oklahoma, Norman. PSM- School of Mines, Paris. RM— Natural History Museum (Riksmuseum), Stockholm. USNM — Department of Paleobiology, U.S. Mu- seum of Natural History, Washington. The remaining institutions, some 27 in all, are given in full in their appropriate place. Bibliographic references are complete so far as known. For brevity, references to pages and to plates and figures apply specifically to Paleozoic polyplacophorans or to comments on the occur- rence of them in the fossil record. Acknowledgments Particular thanks are due to Dr. H. O. Fletcher of the Australian Museum who provided casts of Permochiton australianus and Chelodes cal- ceoloides for study. Dr. G. A. Cooper of the De- partment of Paleobiology, U.S. National Mu- seum, Washington, D.C. was instrumental in providing a loan of the Paleozoic polyplacoph- orans in the museum. Dr. Harry B. Whittington, while at Harvard University, Cambridge, Mas- sachusetts, loaned the Schultz Collection in the Museum of Comparative Zoology for study. The Department of Geology, University of Minne- sota, Minneapolis, Minnesota loaned specimens of Chelodes gibberosus. Dr. Ellis L. Yochelson of the U.S. Geological Survey, Washington, D.C. provided numerous references which were oth- erwise unavailable. Paleozoic Polyplacophoran Fauna The Paleozoic polyplacophoran fauna has well over 150 recorded species, of which 130 named species are believed valid. In addition, 23 oc- currences of valves have been reported, for which no names or formal descriptions have been pro- vided. The 153 forms known at present come from the following geological systems (if the po- sition for a taxon in a system is unclear it is included under Lower): SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA System Lower Middle Upper Total Permian 13 8 1 22 Carboniferous - - - 6 (undifferentiated) Pennsylvanian 4 10 4 18 Mississippian 30 2 1 33 Devonian 7 5 8 20 Silurian 4 8 2 14 Ordovician 21 6 5 32 Cambrian 2 6 Total _8 153 The Cambrian occurrences are reported from the United States and China. The Ordovician taxa are dominantly found in the United States, with a few scattered reports from Czechoslova- kia, Great Britain, Australia, and Canada. Most Silurian taxa are reported from Sweden, with a few occurrences in Ireland, Great Britain, and Australia. The Devonian forms are dominantly from Germany, with a few from France, Czech- oslovakia, Austria, Great Britain, Canada, and the United States. The Carboniferous taxa are reported primarily from Great Britain, Belgium, and the United States. Permian taxa are known mainly from Great Britain and the United States, with scattered forms from Australia and Malay- sia. The bulk of reported recognized species is approximately evenly divided among Great Brit- ain, continental Europe, and North America. Assignment of Species Any student of the Polyplacophora will be aware of the difficulty of preparing a meaningful systematic arrangement of the known fossil species on the basis of present knowledge. Many earlier-described species were placed in the genus Chiton, which was used in a very broad sense; a few were allocated to the genus Chitonellus. Chi- ton, as now restricted, does not include most fossil species and Chitonellus is no longer used. Some fossil chiton species were described from a single valve. In most, the full complement of head, intermediate, and tail valves has not been found. This is a serious detriment to any sound conclusions on proper generic and family place- ment. Of course, the same is true when the qual- ity of the fossils is not good enough to display the characters required for accurate identifica- tion. The differences between many described gen- era rest on inadequate or imperfect information. Except for a few species, it has not been possible to study European Paleozoic species, as much of the original material is in European museums. For many species the location of type or other specimens from original localities has not been reported in the literature; this should be recorded for the benefit of future studies. No complete systematic arrangement can be developed with- out a great deal more study of actual type spec- imens and of related valves from original or equivalent geological formations. The compari- son below between the original systematic allo- cations of Paleozoic polyplacophorans and our assignment is only a short step toward a logical arrangement under appropriate genera, families, and higher taxonomic units. Original assignment Present assignment Acutichiton allynsmithi Hoare, Mapes, and Atwater, 1983 Acutichiton pannuceus Hoare and Mapes, 1985ft Acutichiton pyrmidalus Hoare, Sturgeon, and Hoare, 1972 Anatifopsis? elongatus Hadding, 1913 Arcochiton raymondi Hoare and Sturgeon, 1976 Ascoseras gibberosus Sardeson, 1896 Bursata iowensis Sanders, 1962 Calceochiton cf. C. gibberosus (Sardeson) Flower, 1968 Calceochiton hachitae Flower, 1968 Neoloricata, Acutichitonidae, genus unchanged. Neoloricata, Acutichitonidae, genus unchanged. Neoloricata, Acutichitonidae. Type species of Acutichiton Hoare, Sturgeon, and Hoare, 1972. Paleoloricata, Septemchitonidae, Solenocarisl Young and Young, 1868. Neoloricata, Acutichitonidae. Type species of Arcochiton Hoare and Sturgeon, 1976. Paleoloricata, Mattheviidae, Chelodes Davidson and King, 1874. Paleoloricata, Septemchitonidae, Septemchiton Bergenhayn, 1955. Paleoloricata, Mattheviidae, genus unchanged. Paleoloricata, Mattheviidae. Type species of Calceochiton Flower, 1968. OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 Original assignment Present assignment Calyplraea antiquus Howse, 1848 Camptochiton squarrosus DeBrock, Hoare, and Mapes, 1984 Chauliochiton knighti Hoare and Smith, 1984 Chelodes bergmani Davidson and King, 1874 Chelodes calceoloides Etheridge, 1897 Chelodes depressus Bergenhayn, 1 960 Chelodes gotlandicus Lindstrom, 1884 Chelodes intermedins Bergenhayn, 1960 Chelodes longissimus Bergenhayn, 1955 Chelodes variegatus Bergenhayn, 1955 Chelodes whitehousei Runnegar, Pojeta, Taylor, and Collins, 1979 Chiton armstrongianus Etheridge, 1882 Chiton barrandeanus de Ryckholt, 1852 Chiton bohemicus Barrande, 1867 Chiton burrowianus Kirkby, 1862 Chiton canadensis Billings, 1865 Chiton carbonarius Stevens, 1858 Chiton collinensis Gortani, 1913 Chiton coloratus Kirkby, 1 862 Chiton concentricus de Koninck, 1 842 Chiton"! cordatus Kirkby, 1859 Chiton? cordatus? Kirkby and Young, 1867 Chiton cordatus Etheridge, 1882 Chiton? cordiferde Koninck, 1842 Chiton cordiformis Sandberger, 1845 Chiton corrugatus Sandbergerand Sandberger, 1856 [non Reeve, 1848] Chiton dalriensis Etheridge, 1882 Chiton eburonicus de Ryckholt, 1845 Chiton exsectionis Trenkner, 1868 Chiton fasciatus Sandberger, 1842 Chiton geikei Etheridge, 1882 Chiton gemmatus de Koninck, 1 842 Chiton gibbosus Trenkner, 1868 Chiton grayanus de Koninck, 1857 Chiton howseanus Kirkby, 1857 Chiton humilis Kirkby in Young, 1865 Chiton inflatus Trenkner, 1868 Chiton laevigatus Roemer, 1855 Chiton legiacus de Ryckholt, 1845 Chiton loftusianus King, 1 848 Chiton mempiscus de Ryckholt, 1845 Chiton mosensis de Ryckholt, 1845 Neoloricata, Lepidopleuridae. Type species of Camptochiton DeBrock, Hoare, and Mapes, 1984. Neoloricata, Lepidopleuridae. Type species of Chauliochiton Hoare and Smith, 1984. Paleoloricata, Mattheviidae. Type species of Chelodes David- son and King, 1874. Paleoloricata, Mattheviidae, genus unchanged. Paleoloricata, Mattheviidae, genus unchanged. Paleoloricata, Mattheviidae, genus unchanged. Paleoloricata, Mattheviidae, genus unchanged. Paleoloricata, Mattheviidae, genus unchanged. Paleoloricata, Mattheviidae, genus unchanged. Paleoloricata, Mattheviidae, genus unchanged. Neoloricata, Lepidopleuridae, Gryphochiton? Gray, 1847a. * Paleoloricata, Mattheviidae, Chelodes. t Order and family unknown. Type species of Priscochiton Dall, 1882. Neoloricata, Lepidopleuridae. Type species of Glaphurochiton Raymond, 1910. t t . Neoloricata, Lepidopleuridae, Pterochiton? Carpenter in Dall, 1882. Neoloricata, Lekiskochitonidae, Lekiskochiton? Hoare and Smith, 1984. Neoloricata, Lepidopleuridae. See Gryphochiton? acutivalis (de Koninck, 1883). Neoloricata, Acutichitonidae, Acutichiton Hoare, Sturgeon, and Hoare, 1972. Neoloricata, Glyptochitonidae. Type species of Glyptochiton de Koninck, 1883. t Paleoloricata, Chelodidae. Type species of Proboleaum Car- penter in Dall, 1882. Neoloricata, Permochitonidae, Pileochiton DeBrock, Hoare, and Mapes, 1984. Neoloricata, Lepidopleuridae. Type species of Pterochiton Car- penter in Dall, 1882. t Nomen nudum, preoccupied. Replaced by Chiton sagittalis Sandberger and Sandberger, 1853, which is rejected as a chiton for the purpose of this report. Neoloricata, Lepidopleuridae, Chauliochiton? Hoare and Smith, 1984. Preoccupied. Replaced by Chiton subgemmatus d'Orbigny, 1850. Neoloricata, Lepidopleuridae, Pterochiton Carpenter in Dall, 1882. t t Neoloricata, Cymatochitonidae, Cymalochiton? Dall, 1882. t t t Neoloricata, Lepidopleuridae, Pterochiton Carpenter in Dall, 1882. Neoloricata, Cymatochitonidae. Type species of Cymatochiton Dall, 1882. Neoloricata, Lepidopleuridae, Gryphochiton Gray, 1 847a. Neoloricata, Lepidopleuridae, Pterochiton? Carpenter in Dall, 1882. SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA Original assignment Present assignment Chiton nervicanus de Ryckholt, 1845 Chiton occidentalis Foster, 1837 Chiton orbiculus Trenkner, 1868 Chiton parvus Stevens, 1 858 Chiton priscus Minister, 1 839 Chiton priscus Sandberger, 1 842 Chiton sagittalis Sandberger and Sandberger, 1853 Chiton sandbergianus de Ryckholt, 1845 Chiton scaldianus de Ryckholt, 1852 Chiton sluseanus de Ryckholt, 1845 Chiton soleaformis Etheridge, 1882 Chiton subgemmatus d'Orbigny, 1850 Chiton subgranosus Sandberger, 1842 Chiton symmetricus Trenkner, 1868 Chiton thomodiensis Baily, 1859 Chiton tornaciola de Ryckholt, 1845 Chiton trapezoidalis Trenkner, 1868 Chiton tumidus de Koninck, 1857 Chiton turnacianus de Ryckholt, 1845 Chiton viseticola de Ryckholt, 1845 Chiton woodmillensis Dunlop, 1915 Chiton wrightianus de Koninck, 1857 Chitonellus bennieanus Etheridge, 1882 Chitonellus distortus Kirkby, 1859 Chitonellus hancockianus Kirkby, 1859 Chitonellus kirkbyanus Etheridge, 1882 Chitonellus! patelliformis Etheridge, 1882 Chitonellus quadratus Etheridge, 1882 Chitonellus! subantiquus Kirkby and Young, 1867 Chitonellus subquadratus Kirkby and Young, 1867 Chitonellus youngianus Kirkby in Young, 1865 Cobcrephora corrugata Bischoff, 1981 Cobcrephora silurica Bischoff, 1981 Cobcrephora cf. silurica Bischoff, 1981 Colapterochiton decorus Hoare and Mapes, 1985a Coryssochiton parallelus DeBrock, Hoare, and Mapes, 1 984 Cymatochiton ryckholtianus Dall, 1 882 Cymatochiton! texanus Girty, 1909 Duslia insignis Jahn, 1893 Elachychiton juxtaterminus Hoare and Mapes, 1985a Eochelodes bergenhayni Marek, 1962 Eochiton arbucklensis Smith in Smith and Toomey, 1964 Euleptochiton torus Hoare and Mapes, 1985a Glaphurochiton simplex Raymond, 1910 Gotlandochiton birhombivalvis Bergenhayn, 1955 Gotlandochiton hami Smith in Smith and Toomey, 1 964 Neoloricata, Lepidopleuridae. Type species of Gryphochiton Gray, 1847a, b. Neoloricata, Lepidopleuridae, Gryphochiton Gray , 1847a. Neoloricata, Lepidopleuridae, Gryphochiton Gray, 1847a. Preoccupied, see Chiton sandbergianus de Ryckholt, 1845. * Neoloricata, Lepidopleuridae, Pterochiton Carpenter in Dall, 1882. * Neoloricata, Lepidopleuridae. Synonym of P. subgemmatus d'Orbigny, 1850. Neoloricata, Acutichitonidae, Soleachiton Hoare and Smith, 1984. Neoloricata, Lepidopleuridae, Pterochiton Carpenter in Dall, 1882. Nomen nudum. See Chiton corrugatus Sandberger and Sand- berger, 1856. Neoloricata, Lepidopleuridae. Synonym of P. corrugatus (Sandberger and Sandberger, 1856). Neoloricata, Lepidopleuridae, Pterochiton Carpenter in Dall, 1882. * t t Neoloricata, Lepidopleuridae, Gryphochiton Gray, 1847a. Neoloricata, Lepidopleuridae, Gryphochiton Gray, 1847a. t Neoloricata, Glyptochitonidae, Glyptochiton de Koninck, 1883. * Neoloricata, Glyptochitonidae, Glyptochiton de Koninck, 1883. * Neoloricata, Glyptochitonidae, Glyptochiton de Koninck, 1883. Neoloricata, Glyptochitonidae, Glyptochiton de Koninck, 1883. Phosphatoloricata, Cobcrephoridae, genus unchanged. Phosphatoloricata, Cobcrephoridae. Type species of Cobcre- phora Bischoff 1981. Phosphatoloricata, Cobcrephoridae, genus unchanged. Neoloricata, Lepidopleuridae, genus unchanged. Neoloricata, Lepidopleuridae. Type species of Coryssochiton DeBrock, Hoare, and Mapes, 1984. Nomen nudum. Neoloricata, Lepidopleuridae, Pterochiton Carpenter in Dall, 1882. Neoloricata, Cymatochitonidae, genus unchanged. Neoloricata, Acutichitonidae, genus unchanged. Paleoloricata, Chelodidae. Type species of Eochelodes Marek, 1962. Paleoloricata, Gotlandochitonidae. Type species of Kindbla- dochiton Van Belle, 1975a. Neoloricata, Permochitonidae, genus unchanged. Neoloricata, Lepidopleuridae, Gryphochiton Gray, 1847a. Paleoloricata, Gotlandochitonidae, genus unchanged. Paleoloricata, Gotlandochitonidae, genus unchanged. OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 Original assignment Present assignment Gotlandochiton interplicatus Bergenhayn, 1955 Gotlandochiton laterodepressus Bergenhayn, 1955 Gotlandochiton troedssoni Bergenhayn, 1955 Gryphochiton triangulatum Carpenter in Dall, 1882 Helminthecella expansa Ulrich and Bridge in Butts, 1 94 1 Helminthochiton aequivoca Robson, 1913 Helminthochiton coarctatus de Koninck, 1883 Helminthochiton concinnus Richardson, 1956 Helminthochiton girtyi Hoare and Smith, 1984 Helminthochiton grayiae Woodward, 1885 Helminthochiton griffithi Salter in McCoy, 1 846 Helminthochiton mucronotus de Koninck, 1883 Helminthochiton lebescontei Barrois, 1889 Helminthochiton priscoides Carpenter in Dall, 1882 Helminthochiton procumbens de Koninck, 1883 Helminthochiton riddlei Frederickson, 1962 Helminthochiton! secundus Horny in Spinar 1965 Helminthochiton thraivensis Reed, 1911 Ivoechiton calathicolus Smith in Smith and Toomey, 1 964 Ivoechiton oklahomensis Smith in Smith and Toomey, 1964 Lekiskochiton fornicis Hoare and Smith, 1984 Lepidopleurus laterodepressus Bergenhayn, 1945 Llandeilochiton ashbyi Bergenhayn, 1955 Luyanhaochiton spinus Yii, 1984 Matthevia variabilis Walcott, 1885 Matthevia walcotti Runnegar, Pojeta, Taylor, and Collins, 1 979 Ochmazochiton comptus Hoare and Smith, 1984 Paleochiton kindbladensis Smith in Smith and Toomey, 1 964 Pedanochiton discomptus DeBrock, Hoare, and Mapes, 1984 Permochiton australianus Iredale and Hull, 1926 Pileochiton cancellus DeBrock, Hoare, and Mapes, 1984 Platyceras anomalus Rowley, 1 908 Preacanthochiton cooperi Bergenhayn, 1 960 Preacanthochiton &S. cooperi Bergenhayn, 1960 Preacanthochiton depressus Bergenhayn, 1960 Preacanthochiton productus Bergenhayn, 1960 Priscochiton? mirabilis Butts, 1 926 Priscochiton? sellaeformis Butts, 1926 Probolaeuml canadense Clarke, 1 907 Protalochiton settlensis Rochebrune, 1883 Pterochiton arthurcooperi Smith, 1976 Paleoloricata, Gotlandochitonidae. Type species of Gotlan- dochiton Bergenhayn, 1955. Paleoloricata, Gotlandochitonidae, genus unchanged. Paleoloricata, Gotlandochitonidae, genus unchanged. Neoloricata, Lepidopleuridae, genus unchanged. Paleoloricata, Mattheviidae. Type species of Helminthecella Ulrich and Bridge in Butts, 1941. Neoloricata, Helminthochitonidae, genus unchanged. Neoloricata, Lepidopleuridae. Synonym of G. priscus (Minis- ter, 1839). Neoloricata, Lepidopleuridae, Glaphurochiton Raymond, 1910. Neoloricata, Lepidopleuridae, Gryphochiton Gray, 1847a. Paleoloricata, Septemchitonidae. Type species of Septemchi- ton Bergenhayn, 1955. Neoloricata, Helminthochitonidae. Type species of Helmin- thochiton Salter in McCoy, 1846. Neoloricata, Lepidopleuridae. Synonym of G. priscus (Miins- ter, 1839). Neoloricata, Permochitonidae, Euleplochiton? Hoare and Mapes, 1985a. Neoloricata, Lepidopleuridae, Gryphochiton Gray, 1847a. Neoloricata, Lepidopleuridae, Gryphochiton Gray, 1847a. Neoloricata, Lepidopleuridae, Glaphurochiton? Raymond, 1910. Neoloricata, Helminthochitonidae, genus unchanged. Paleoloricata, Septemchitonidae, Septemchitonl Bergenhayn, 1955. Paleoloricata, Scanochitonidae, genus unchanged. Paleoloricata, Scanochitonidae, genus unchanged. Neoloricata, Lekiskochitonidae. Type species of Lekiskochiton Hoare and Smith, 1984. Neoloricata, Lepidopleuridae. Type species of Proleptochiton Sirenko and Starobogatov, 1977. Order and family unknown, genus unchanged. Paleoloricata, Mattheviidae. Type species of Matthevia Wal- cott, 1885. Paleoloricata, Mattheviidae, genus unchanged. Neoloricata, Heterochitonidae. Type species of Ochmazochi- ton Hoare and Smith, 1984. Paleoloricata, Gotlandochitonidae. Type species of Paleochi- ton Smith in Smith and Toomey, 1964. Neoloricata, Cymatochitonidae. Type species of Pedanochiton DeBrock, Hoare, and Mapes, 1984. Neoloricata, Permochitonidae. Type species of Permochiton Iredale and Hull, 1926. Neoloricata, Permochitonidae. Type species of Pileochiton DeBrock, Hoare, and Mapes, 1984. Neoloricata, Ochmazochitonidae? Type species of Lobarochi- ton Hoare, 1976. Paleoloricata, Preacanthochitonidae. Type species of Preacan- thochiton Bergenhayn, 1960. Paleoloricata, Preacanthochitonidae, genus unchanged. Paleoloricata, Preacanthochitonidae, genus unchanged. Paleoloricata, Preacanthochitonidae, genus unchanged. Paleoloricata, Mattheviidae, Chelodesl Davidson and King, 1874. Paleoloricata, Mattheviidae, Chelodes Davidson and King, 1874. Paleoloricata, Chelodidae, genus unchanged. Order and family unknown. Type species of Protalochiton Rochebrune, 1883. Neoloricata, Lepidopleuridae, genus unchanged. SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA Original assignment Present assignment Pterochiton elevatus Kues, 1978 Pterochiton newelli Smith, 1976 Pterochiton spatulatus Hoare, Sturgeon, and Hoare, 1972 Pterochiton tholus Hoare, Mapes, and Atwater, 1983 Rhombichiton acutivalvis de Koninck, 1883 Rhombichiton kirkbyi de Koninck, 1883 Rhombichiton ochtinensis Turek and Prokop, 1982 Rhynchoteuthis kaibabensis Brady, 1955 Sagmaplaxus sarthacensis Oehlert, 1 88 1 Septemchiton iowensis Sanders, 1965 Septemchiton vermiformis Bergenhayn, 1955 Soleachiton yochelsoni Hoare and Smith, 1984 Solenocaris solenoides Young and Young, 1 868 Stegochiton coxi Hoare and Smith, 1984 Stegochiton? onerosus Hoare and Smith, 1984 Sulcochiton grayi de Ryckholt, 1862 Yangtzechiton elongatus Yii, 1984 Neoloricata, Lepidopleuridae, Gryphochiton Gray, 1847a. Neoloricata, Lepidopleuridae, genus unchanged. Neoloricata, Permochitonidae. Type species of Euleptochiton Hoare and Mapes, 1985a. Neoloricata, Permochitonidae, Euleptochiton Hoare and Mapes, 1985a. Neoloricata, Lepidopleuridae, Gryphochiton"? Gray, 1847a. Neoloricata, Cymatochitonidae, Cymatochitonl Dall, 1882. Neoloricata, Lepidopleuridae, Proleptochiton Sirenko and Sta- robogatov, 1977. Neoloricata, Cymatochitonidae, Cymatochiton? Dall, 1882. Paleoloricata, Chelodidae, Chelodesl Davidson and King, 1874. Paleoloricata, Septemchitonidae, genus unchanged. Paleoloricata, Septemchitonidae. Synonym of S. grayiae Woodward, 1885. Neoloricata, Acutichitonidae. Type species of Soleachiton Hoare and Smith, 1984. Paleoloricata, Septemchitonidae, genus unchanged. Neoloricata, Lepidopleuridae. Type species of Stegochiton Hoare and Smith, 1984. Neoloricata, Lepidopleuridae, genus unchanged. Order and family unknown, genus unchanged. * Rejected as a chiton for the purpose of this report. t Impossible to place systematically. Systematic Arrangement Based on the summary listing, and on some tentative conclusions on systematic placement contained in discussions of individual species in the appended checklist, the following family ar- rangement for species is offered as a starting point for future students of Paleozoic polyplacopho- rans. A question mark after a taxon indicates a problematical assignment. Ever since Lamarck (1802) described the first fossil polyplacophoran, attempts have been made to construct a classification encompassing both fossil and modern forms. In making generic and family assignments herein the following criteria, which are believed to be significant in the phy- logeny of the polyplacophorans, have been used. They are listed in approximate order of their importance in the hierarchy of the classification. 1— Composition of the valves. 2— Development of an articulamentum layer. 3— Shape of valves. 4— Shape and extent of the sutural laminae. 5 —Development of insertion plates, unslitted and slitted. 6— Development of lateral, central, and poste- rior valve areas. 7— Ornamentation. Progressive changes in the sutural laminae, in- sertion plates, and valve areas should be ex- pected within a family as well as differences in valve shape and ornamentation. The families Chelodidae in the Paleoloricata and Lepidopleuridae in the Neoloricata are re- tained, as broadly defined, to encompass taxa which are not assigned to more narrowly defined familial groupings. The Paleozoic polyplacoph- orans are still so poorly known that the over- splitting at the family level is premature. Class POLYPLACOPHORA de Blainville, 1816 Subclass PALEOLORICATA Bergenhayn, 1955 Order Chelodina Bergenhayn, 1943 Family Chelodidae Bergenhayn, 1943 Eochelodes bergenhayni Marek, 1962 — Middle Ordovician, Czechoslovakia. Probolaeuml canadense Clarke, 1 907 — Lower Devonian, Can- ada. Probolaeum corrugatus Sandberger and Sandberger, 1 856 — Middle Devonian, Germany. Family Mattheviidae Walcott, 1886 Calceochiton cf. C. gibberosus Flower, 1968 — Lower Ordovi- cian, USA (Wisconsin). Calceochiton hachitae Flower, 1968 — Lower Ordovician, USA (New Mexico). Chelodes bergmani Davidson and King, 1874 — Middle Silu- rian, Sweden. OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 Chelodes bohemicus (Barrande, 1867) — Upper Silurian, Czechoslovakia. Chelodes calceoloides Etheridge, 1897 — Upper Silurian, Aus- tralia. Chelodes depressus Bergenhayn, 1960— Lower Ordovician, USA (Missouri). Chelodes gibberosus (Sardeson, 1896)— Lower Ordovician, USA (Minnesota). Chelodes got landicus Lindstrom, 1 884— Middle Silurian, Swe- den. Chelodes intermedins Bergenhayn, 1960— Lower Ordovician, USA (Virginia). Chelodes longissimus Bergenhayn, 1955 — Middle Ordovician, Scotland. Chelodes? mirabilis (Butts, 1926)— Lower Ordovician, USA (Alabama). Chelodes? sarthacensis (Oehlert, 1881)— Lower Devonian, France. Chelodes sellaeformis (Butts, 1926)— Middle Ordovician, USA (Alabama). Chelodes variegatus Bergenhayn, 1955 — Middle Silurian, Swe- den. Chelodes whitehousei Runnegar, Pojeta, Taylor, and Collins, 1979 — Lower Ordovician, Australia. Helmithecella expansa Ulrich and Bridge in Butts, 1 94 1 — Low- er Ordovician, USA (Missouri). Matthevia variabilis Walcott, 1885 — Upper Cambrian, USA (New York). Matthevia walcotti Runnegar, Pojeta, Taylor, and Collins, 1979— Upper Cambrian, USA (Wisconsin). Family Gotlandochitonidae Bergenhayn, 1955 Gotlandochiton birhombivalvis Bergenhayn, 1955 — Middle Si- lurian, Sweden. Gotlandochiton hami Smith in Smith and Toomey, 1964— Lower Ordovician, USA (Oklahoma). Gotlandochiton interplicatus Bergenhayn, 1955 — Middle Si- lurian, Sweden. Gotlandochiton laterodepressus Bergenhayn, 1 955 — Middle Si- lurian, Sweden. Gotlandochiton troedssoni Bergenhayn, 1955 — Middle Siluri- an, Sweden. Kindbladochiton arbucklensis (Smith in Smith and Toomey, 1964)— Lower Ordovician, USA (Oklahoma). PaleochitonkindbladensisSmith in Smith and Toomey, 1964 — Lower Ordovician, USA (Oklahoma). Family Preacanthochitonidae Bergenhayn, 1 960 Preacanthochiton cooperi Bergenhayn, 1960 — Upper Cambri- an, USA (Missouri). Preacanthochiton aff. P. cooperi Bergenhayn, 1960— Upper Cambrian, USA (Missouri). Preacanthochiton depressus Bergenhayn, 1960 — Lower Ordo- vician, USA (Missouri). Preacanthochiton productus Bergenhayn, 1960— Upper Cam- brian, USA (Missouri). Family Scanochitonidae Bergenhayn, 1 943 Ivoechiton calathicolus Smith in Smith and Toomey, 1964— Lower Ordovician, USA (Oklahoma). Ivoechiton oklahomensis Smith in Smith and Toomey, 1 964— Lower Ordovician, USA (Oklahoma). Family Septemchitonidae Bergenhayn, 1955 Septemchiton iowensis (Sanders, 1962)— Upper Ordovician, USA (Iowa). Septemchiton grayiae (Woodward, 1885)— Middle Ordovi- cian, Scotland. Septemchiton? thraivensis (Reed, 191 1)— Middle Ordovician, Scotland. Solenocaris elongata (Hadding, 1913)— Upper Ordovician, Sweden. Solenocaris solenoides Young and Young in Young, 1868 — Upper Ordovician, Scotland. Subclass PHOSPHATOLORICATA Bischoff, 1981 Order Phosphatoloricatina Bischoff, 1981 Family Cobcrephoridae Bischoff, 1981 Cobcrephora corrugata Bischoff, 1 98 1 — Middle Silurian, Aus- tralia. Cobcrephora silurica Bischoff, 1981 —Upper Ordovician to Late Silurian, Australia. Cobcrephora cf. silurica Bischoff, 1981 —Lower Silurian, Aus- tralia. Subclass NEOLORICATA Bergenhayn, 1955 Order Lepidopleurina Thiele, 1910 Family Acutichitonidae Hoare, Mapes, and Atwater, 1983 Acutichiton allynsmithi Hoare, Mapes, and Atwater, 1983 — Lower Pennsylvanian, USA (Oklahoma). Acutichiton etheridgei n. sp. — Lower Carboniferous, England. Acutichiton pannuceus Hoare and Mapes, 1985ft— Upper Pennsylvanian, USA (Texas). Acutichiton pyrmidalus Hoare, Sturgeon, and Hoare, 1972 — Middle Pennsylvanian, USA (Ohio). Arcochiton raymondi Hoare and Sturgeon, 1976 — Middle Pennsylvanian, USA (Ohio). Elachychiton juxtatermis Hoare and Mapes, 1985a — Upper Mississippian, USA (Arkansas). Soleachiton soleaformis (Etheridge, 1882)— Lower Carbonif- erous, Scotland. Soleachiton yochelsoni Hoare and Smith, 1984 — Lower and Middle Permian, USA (Texas). Family Cymatochitonidae Sirenko and Starobogatov, 1977 Cymatochiton? howseanus (Kirkby, 1857) — Permian, En- gland. Cymatochiton? kaibabensis (Brady, 1955)— Middle Permian, USA (Arizona). Cymatochiton? kirkbyi (de Koninck, 1883)— Lower Carbon- iferous, England. Cymatochiton loftusianus (King, 1850)— Upper Permian, En- gland. Cymatochiton? texanus Girty, 1909 — Middle Permian, USA (Texas). Pedanochiton discomptus DeBrock, Hoare, and Mapes, 1 984— Middle Pennsylvanian, USA (Texas). Family Glyptochitonidae Starobogatov and Sirenko, 1975 Glyptochiton cordifer (de Koninck, 1844)— Lower Carbonif- erous, Belgium. SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA Glyptochiton kirkbyanus (Etheridge, 1882)— Lower Carbonif- erous, Scotland. Glyptochiton quadratus (Etheridge, 1882)— Lower Carbonif- erous, Scotland. Glyptochiton subquadratus (Kirkby and Young, 1867)— Car- boniferous, Scotland. Glyptochiton youngianus (Kirkby in Young, 1865)— Lower Carboniferous, Scotland. Family Lekiskochitonidae n. fam. Lekiskochiton? cordatus (Kirkby, 1859)— Permian, England. Lekiskochiton fornicis Hoare and Smith, 1 984 — Middle Perm- ian, USA (Texas). Family Lepidopleuridae Pilsbry, 1892 Camptochiton squarrosus DeBrock, Hoare, and Mapes, 1984 — Middle Pennsylvanian, USA (Texas). Chauliochiton? geikei (Etheridge, 1882)— Lower Carbonifer- ous, Scotland. Chauliochiton knighti Hoare and Smith, 1984 — Lower and Middle Permian, USA (Texas). Colapterochiton decorus Hoare and Mapes, 1985a — Lower Pennsylvanian, USA (Oklahoma). Coryssochiton parallelus DeBrock, Hoare, and Mapes, 1984 — Middle Pennsylvanian, USA (Texas). Glaphurochiton carbonarius (Stevens, 1858)— Middle Penn- sylvanian, USA (Illinois). Glaphurochiton concinnus (Richardson, 1956)— Middle Penn- sylvanian, USA (Illinois). Glaphurochiton? riddlei (Frederickson, 1962) — Upper Penn- sylvanian, USA (Oklahoma). Gryphochiton? acutivalvis (de Koninck, 1883)— Lower Car- boniferous, England. Gryphochiton? armstrongianus (Etheridge, 1882)— Carbonif- erous, Scotland. Gryphochiton elevatus (Kues, 1978)— Middle Mississippian, USA (Indiana). Gryphochiton girtyi (Hoare and Smith, 1984)— Middle Perm- ian, USA (Texas). Gryphochiton mempiscus (de Ryckholt, 1845)— Lower Car- boniferous, Belgium. Gryphochiton nervicanus (de Ryckholt, 1845)— Lower Car- boniferous, Belgium. Gryphochiton parvus (Stevens, 1858)— Middle Mississippian, USA (Indiana). Gryphochiton priscoides (Carpenter in Dall, 1882)— Devonian, Germany. Gryphochiton priscus (Minister, 1 839)— Lower Carboniferous, Belgium. Gryphochiton procumbens (de Koninck, 1883)— Lower Car- boniferous, Belgium. Gryphochiton simplex (Raymond, 19 10) -Middle Pennsyl- vanian, USA (Pennsylvania). Gryphochiton triangulatum Carpenter in Dall, 1882 — Lower Carboniferous, Belgium. Gryphochiton turnacianus (de Ryckholt, 1845)— Lower Car- boniferous, Belgium. Gryphochiton viseticola (de Ryckholt, 1845)— Lower Carbon- iferous, Belgium. Helminthochiton? aequivoca Robson, 1913 — Lower Ordovi- cian, Czechoslovakia. Helminthochiton griffithi Salter in McCoy, 1846— Lower Si- lurian, Ireland. Helminthochiton? secundus Horny in Spinar, 1 965 — Devonian, Czechoslovakia. Proleptochiton laterodepressus (Bergenhayn, 1945)— Carbon- iferous, Scotland. Proleptochiton ochtinensis (Turek and Prokop, 1982) — Upper Carboniferous, Czechoslovakia. Pterochiton arthurcooperi Smith, 1976 — Middle Permian, USA (Texas). Pterochiton? concentricus (de Koninck, 1844)— Lower Car- boniferous, Belgium. Pterochiton eburonicus (de Ryckholt, 1845)— Lower Carbon- iferous, Belgium. Pterochiton legiacus (de Ryckholt, 1845)— Lower Carbonif- erous, Belgium. Pterochiton? mosensis (de Ryckholt, 1845)— Lower Carbon- iferous, Belgium. Pterochiton newelli Smith, 1 976 — Middle Permian, USA (Tex- as). Pterochiton papilio (Whidborne, 1892)— Devonian, England. Pterochiton ryckholtianus (Dall, 1 882)— Lower Carboniferous, Belgium. Pterochiton sandbergianus (de Ryckholt, 1845)— Middle De- vonian, Germany. Pterochiton subgemmatus (d'Orbigny, 1 850)— Lower Carbon- iferous, Belgium. Pterochiton thomodiensis (Baily, 1859)— Carboniferous, Ire- land. Stegochiton coxi Hoare and Smith, 1984 — Lower Permian, USA (Texas). Stegochiton? onerosus Hoare and Smith, 1984 — Lower Perm- ian, USA (Texas). Family Heterochitonidae Van Belle, 1978 Lobarochiton anomalus (Rowley, 1908)— Upper Devonian, USA (Missouri). Ochmazochiton comptus Hoare and Smith, 1984 — Lower and Middle Permian, USA (Texas). Family Permochitonidae Sirenko and Starobogatov, 1977 Euleptochiton lebescontei (Barrois, 1889)— Lower Devonian, France. Euleptochiton spalulatus (Hoare, Sturgeon, and Hoare, 1972) — Middle Pennsylvanian, USA (Ohio). Euleptochiton tholus (Hoare, Mapes, and Atwater, 1983) — Lower Pennsylvanian, USA (Oklahoma). Euleptochiton torus Hoare and Mapes, 1985a — Upper Penn- sylvanian, USA (Texas). Permochiton australianus Iredale and Hull, 1926— Permian, Australia. Pileochiton cancellus DeBrock, Hoare, and Mapes, 1 984 — Middle Pennsylvanian, USA (Texas). Pileochiton dalriensis (Etheridge, 1882)— Lower Carbonifer- ous, Scotland. Order and Family Indeterminate Luyanhaochiton spinus Yu, 1984— Lower Cambrian, China. Priscochiton canadensis (Billings, 1865) — Middle Ordovician, Canada. 10 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 Protalochiton settlensis Rochebrune, 1883 — Lower Carbonif- erous, England. Yangtzechiton elongatus Yii, 1984 — Lower Cambrian, China. Family and Genus Indeterminate "Chiton" burrowianus Kirkby, 1862 — Lower Carboniferous, England. "Chiton" collinensis Gortani, 1913 — Lower Devonian, Aus- tria. "Chiton" coloratus (Kirkby, 1 862)— Lower Carboniferous, En- gland. "Chiton" cordiformis Sandberger, 1845 — Middle Devonian, Germany. "Chiton" exsectionis Trenkner, 1868 — Upper Devonian, Ger- many. "Chiton" gibbosus Trenkner, 1868 — Upper Devonian, Ger- many. "Chiton" grayanus de Koninck, 1857 — Lower Silurian, En- gland. "Chiton" humilis Kirkby in Young, 1865— Carboniferous, Scotland. "Chiton" inflatus Trenkner, 1868 — Upper Devonian, Ger- many. "Chiton" laevigatus Roemer, 1855 — Upper Devonian, Ger- many. "Chiton" orbiculus Trenkner, 1868 — Upper Devonian, Ger- many. "Chiton" trapezoidalis Trenkner, 1868 — Upper Devonian, Germany. "Chiton" tumidus de Koninck, 1857 — Upper Devonian, Ger- many. "Chiton" woodmillensis Dunlop, 1915 — Lower Carbonifer- ous, Scotland. Rejected as Polyplacophora Calyptraea antiqua Howse, 1848 — Permian, England. Chiton barrandeanus de Ryckholt, 1852 — Lower Carbonifer- ous, Belgium. Chiton occidentalis Foster, 1837 — Pennsylvanian, USA (Ohio). Chiton sagittalis Sandberger and Sandberger, 1856 — Middle Devonian, Germany. Chiton scaldianus de Ryckholt, 1852 — Lower Carboniferous, Belgium. Chiton tornaciola de Ryckholt, 1845 — Late Carboniferous, Belgium. Chiton wrightianus de Koninck, 1857 — Middle Silurian, En- gland. Chitonellus bennieanus Etheridge, 1882 — Lower Carbonifer- ous, Scotland. Chitonellus distortus Kirkby, 1859 — Permian, England. Chitonellus hancockianus Kirkby, 1859— Permian, England. Chitonellus patelliformis Etheridge, 1882— Lower Carbonif- erous, Scotland. Chitonellus? subantiquus Kirkby and Young, 1867 — Lower Carboniferous, England. Duslia insignis Jahn, 1893— Lower Silurian, Bohemia. Llandeilochiton ashbyi Bergenhayn, 1955 — Middle Ordovi- cian, Scotland. Sulcochiton grayi de Ryckholt, 1862 — Lower Carboniferous, Belgium. Checklist acutivalvis (de Koninck, 1883), Gryphochiton? Chiton? cordatus Kirkby and Young, 1867:341, pi. 16, fig. 10, 1 la-b [non Etheridge 1 882:93-94, pi. 1 , figs. 20-22]. Dunlop 1915:169, pi. 22, fig. 6; 1922:75-76. Rhombichiton acutivalvis de Koninck, 1883:210-211, pi. 53, fig. 30-36. New name. Geological Age. — Lower Carboniferous. Locality. — England: Lower Scar Limestone, Yorkshire (Kirkby and Young). Eastern Scotland: Woodmill, Fife (Dun- lop). Location of Material.— Collections of J. Bennie, J. Smith, etc. (fide Etheridge). Present location unknown. Remarks. — Chiton? cordatus? Kirkby and Young (1867), with good reason, has been con- fused with Chiton? cordatus Kirkby (1859). It was found in strata of Lower Carboniferous age whereas C.I cordatus Kirkby is a Permian species. De Koninck (1883) gave the Carboniferous species a new name, Rhombichiton acutivalvis, which was a proper step under the circumstances. It is not clear which species Dunlop (1915) had in mind but presumably he was referring to the one from the Carboniferous. Etheridge (1882) thought "Except in a few trivial points the plates I have represented in Figs. 20-22 do not differ from Kirkby's Chiton cordatus, a Permian species." Kirkby and Young illustrated two valves, a head(?) and an intermediate valve. Etheridge (1882) gave a good description of the Carbon- iferous valves he studied. His figure 20 shows a broadly triangular tail valve with pointed apex, rather small, pointed sutural laminae, and a dis- tinct, narrow jugal area bordered by granular lat- eropleural areas. His figure 22 of the ventral side of another tail valve shows an extensive hypo- tyche area. Dunlop's illustration (1915, pi. 22, fig. 6) is not readily identifiable as a polyplacoph- oran although it may well be one. Later (1922), Dunlop concluded that Chiton cordatus, C armstrongianus, and C. gemmatus from Wood- mill, Scotland, were conspecific although his il- lustration of C cordatus as a head plate only appears different from that of Kirkby and Young. Until a final determination can be made based on more and better material than seems to have been available, the British Permian and Carbon- iferous species probably should be separated for taxonomic purposes. Further, Etheridge's (1882) specimens are significantly different from the Permian forms of Kirkby (1859) and those of the SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 11 Carboniferous of Kirkby and Young ( 1 867). They are assigned to the genus Acutichiton Hoare, Sturgeon, and Hoare (1972) with a new specific name A. etheridgei q.v. aequivoca Robson, 1913, Helminthochiton! Helminthochiton aequivoca Robson, 1913:304, fig. 1-3. Horny znSpinar, 1965:320. Geological Age. — Lower Ordovician (Arenigian). Locality. — Bohemia: Sarka and Male Prilepy. Location of Material. — Holotype, BM (N.H.) (fide H. W. Ball). Remarks.— The valves are subquadrate, mi- nute, strongly carinate along the median line, markedly emarginate posteriorly, and lacking in- sertion plates and sutural laminae; dorsal sculp- ture consists of two or three diagonal grooves and numerous fine concentric striae running par- allel to the margins. Length, 5.0 mm; height, 3.5 mm. According to Robson, this species is based on "Chiton sp.?" of Professor Kloucek. The valves are badly preserved, consisting of six approxi- mately complete ones and a number of fragments too poor to be of diagnostic value. The better specimens are imprints in portions of two sep- arate ironstone nodules. Robson says Withers (1926) and Reed (1907) think these fossils are amphineuran and not cirripedian; Robson thinks Helminthochiton aequivoca is nearest to H. grif- fithi Salter in McCoy ( 1 846) and hence refers it to Salter's genus. If, in fact, the valves lack in- sertional laminae, as indicated by Robson, this would place the species in the Paleoloricata rath- er than the Neoloricata, and the assignment to Helminthochiton is incorrect. The proper generic assignment must depend on further study of the original material in the British Museum. allynsmithi Hoare, Mapes, and Atwater, 1983, Acutichiton Acutichiton allynsmithi Hoare, Mapes, and Atwater, 1983:996— 997, fig. 1C, 2A, B, 3A-U, 4A, B, 5N, O. Geological Age. — Lower Pennsylvanian (Morrowan). Locality. — USA: Oklahoma, Gene Autry Formation ex- posed in gullies on east side of unnamed tributary of Sycamore Creek on the Daube Ranch, NW'A NWV« SWA, sec. 2, T 4S, R 4E, Johnson Co. Location of Material. — Holotype, OSU-34790; para- types, OSU-3479 1-34808 and BGSU-4177. Remarks. — Reconstructed specimens are small, reaching a length of approximately 20 mm and a width of 5 mm giving a length to width ratio of 4: 1 . Described from a large number of beautifully preserved plates, which allowed the reconstruction of complete individuals, this species is best distinguished by its recurved elon- gate tail valve. Some intermediate valves show the beginning development of lateral areas. Average dimensions are (mm): Head Intermediate Tail Length Width Height 1.9 3.7 2.1 4.1 3.6 2.7 3.6 2.1 2.0 anomalus (Rowley, 1908), Lobarochiton Platyceras? anomalum Rowley, 1908:90, pi. 19, fig. 15-19. Gryphochiton anomalus (Rowley). Williams 1943:100-101, pi. 9, fig. 19-20. Helminthochiton anomalus (Rowley). Yochelson and Saun- ders 1967:11. Lobarochiton anomalus (Rowley). Hoare 1976:117-118, fig. 1-3 [type species of Lobarochiton Hoare, 1976 by original designation]. Pterochitonl anomalus (Rowley). Hoare and Sturgeon 1979: 178, pi. 2, fig. 1-3. Geological Age. — Upper Devonian. (Williams and earlier workers consider this unit Lower Mississippian.) Locality. — USA: Missouri. "The locality is at the mouth of Buffalo Creek two miles southeast of Louisiana" from wash- ings of the clay seams (Rowley). Location of Material. — Holotype, UI-RX-75, a tail valve, in the Department of Geology, University of Illinois. Second specimen missing. Remarks.— The species is based on two co- types, the length of one being 5.2 mm. Williams believed it was related to Helminthochiton par- vus (Stevens, 1 858), an assignment that now seems incorrect. Rowley's illustrations of his species are much too small for an accurate diagnosis. Hoare and Sturgeon (1979) illustrated one of Rowley's specimens, a tail valve showing dorsal, ventral, and side views. While this valve is some- what eroded along the side-margins and at the anterior end, it has a squarish shape with a high, somewhat pointed mucro positioned about one- third the distance from the posterior end. An- terior to the mucro, the valve is sharply concave, dropping down from the mucro almost vertically for a short distance. There is a narrowly trian- gular jugal area bounded by a pair of shallow grooves or sulci that extend diagonally down from the point of the mucro. There is another pair of shallow grooves that appear to be somewhat 12 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 stronger extending down the sides of the valve. The dorsal surface of the valve's posterior area is sculptured with rounded or slightly elliptical pustules of varying sizes and irregular placement. The valve surface forward of the mucro does not show much sculpture although this may be due to wear or abrasion. Ventrally, the anterior mar- gin of the valve shows evidence of the occurrence of sutural laminae. The valve's posterior edge, however, is cut by a series of short, closely spaced slits forming well-defined teeth, of which 40 or more can be counted extending around the entire posterior edge of the valve. This feature is un- usual in Paleozoic polyplacophoran species, being only partially approximated in the tail valve of Glyptochiton cordifer (de Koninck, 1 844) (Smith 1 97 1 , fig. 14-15). Lobawchiton anomalus (Row- ley, 1908) is totally different and not even dis- tantly related to G. cordifer although the geolog- ical ages of the two species may not be too widely separate as the latter comes from the Carbonif- erous of Belgium. Hoare (1976) proposed a new genus Lobaw- chiton, for this unique Paleozoic form. He as- signed it to the family Lepidopleuridae irrespec- tive of the presence of insertion plates. Lobawchiton is in an uncertain taxonomic po- sition; although for the present it may be ten- tatively assigned to the Heterochitonidae, Van Belle, 1978. antiqua Howse, 1848. Genus incertae sedis Calyptraea antiqua Howse, 1848:242. King 1850:247 (appen- dix). Howse 1857:464, pi. 4, fig. 16-17; 1858:244, 273, pi. 11, fig. 16-17. Yochelson 1971:130. Chitonellus antiquus (Howse). Kirkby 1859:608, 611, 619- 621, pi. 16, fig. 15-23. Baily 1860:94-95 (footnote). Kirkby 1860:254-257, pi. 13, fig. 15-23. Rochebrune 1883:39-40. Etheridge 1882:88-89. Dall 1882:283. Stuckenberg 1898: 163, 346, pi. 3, fig. 25a-b. Branson 1948:760. Chiton antiquus (Howse). Baily 1859:333. Geological Age. — Permian. Locality. — England: Tunstall Hill, Durham. Location of Material.— Type specimen in the Museum of the Geological Survey, Jermyn Street, London (Howse 1858) (now Institute of Geological Sciences and Museum, Exhibition Road). Valves under this name from Gera, Germany, are in the BM (N.H.) (fide H. W. Ball). Remarks.— Baily (1860) included a footnote to the effect that Kirkby changed the allocation of this species to Chitonellus, it "having previ- ously been mistaken by Mr. Howse for a Calyp- traea . . . ." Dall, Rochebrune, Stuckenberg, and Branson all thought specimens identified as Chi- tonellus antiquus (Howse, 1848) probably were not polyplacophorans. Kirkby (1859) covered the species in detail based on a total of 1 0 specimens. His illustrations show rounded valves that are slightly ovate to almost circular in shape, with a sculpture of coarse ribs radiating from a prominent apex, which is generally placed from a slightly to a markedly posterior position. Such a type of sculpture and shape is unusual in Paleozoic polyplacophorans and would appear to have a closer relationship to an ancient patellid gastropod. The status of the species must remain uncer- tain pending further study but is not accepted here as a polyplacophoran. arbucklensis (Smith in Smith and Toomey, 1 964), Kindbladochiton Eochiton arbucklensis Smith in Smith and Toomey, 1964:26- 27, pi. 6, fig. 1-9 [type species of Eochiton Smith, 1964, by original designation]. Kindbladochiton arbucklensis (Smith). Van Belle 1975a: 126, pi. 1, fig. lOa-c. Sirenko and Starobogatov 1977:34, fig. 2d. Geological Age. — Lower Ordovician (Kindblade Forma- tion). Locality. — USA: Oklahoma; lower part of Kindblade For- mation, Mill Creek section, Arbuckle Mts. Location of Material. — Holotype, OU-5217; paratype, USNM- 144540; paratype, CAS- 12592. Remarks.— The species is based on three in- termediate valves acid-etched from limestone blocks. No end valves were found. Preservation is relatively poor. The holotype is 8.8 mm long, 1 1.4 mm wide, and 6.3 mm high. Thickness at the jugum is 3.0 mm. The jugal angle is approx- imately 106°. It has a well-developed apical area 1.8 mm wide at the apex, increasing to 2.0 mm near the margins. The name Eochiton was first used by Fischer (1885) in a general classification of fossil poly- placophorans as a subgenus of Holochiton Fi- scher, 1 8 8 5 . At the time Smith (1964) introduced Eochiton as a genus the name was considered available for subsequent valid use. Van Belle (1975<3) subsequently proposed a new name, Kindbladochiton, which has clarified this taxo- nomic situation. armstrongianus (Etheridge, 1882), Gryphochitonl Chiton sp. Kirkby and Young, 1867:341, pi. 16, fig. 7a-c, 9. Chiton armstrongianus Etheridge, 1882:89-91, pi. 1, fig. 15. Dunlop 1915:169, pi. 22, fig. 2-3; 1922:75-76. SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 13 Geological Age. — Carboniferous. Locality.— Scotland: Lower and upper limestone of Crai- genglen, Williamwood, near Cathcart, Renfrewshire (Kirkby and Young). Williamwood, near Glasgow, in shales of the Or- chard Limestone, Upper Carboniferous group; also from Cun- ningham Baidland, near Dairy, in Lower Carboniferous shale (Etheridge). Location of Material. — Collections of J. Armstrong and J. Bennie (fide Etheridge). Specimens with the label "Chiton armstrongi Eth. jun." are in the BM (N.H.) (fide H. W. Ball). Remarks. — Chiton sp. Kirkby and Young (1867) is based on three tail valves showing well- developed, rounded sutural laminae. Dimen- sions given are: length, % inch (5 mm); width, a little less. These authors thought their specimens approached those of Chiton burrowianus Kirkby, 1862 quite closely. Etheridge (1882) gave a good account of this species based on original material cited by Kirk- by and Young (1867) and valves collected later. Etheridge said Chiton armstrongianus may be distinguished from other species, first by the form of the valves, and second, by the coarseness of the dorsal sculpture, "which resembles, more than anything, the teething of a rasp, or coarse file." In comparing it with C humilis Kirkby in Young (1865) Etheridge said C armstrongianus is "more pointed behind, and less acute in front; the im- pressed concentric grooves less in number; whilst the portion of the plate posterior to the apex is a gradual slope from the latter to the posterior margin, and not nearly as flat as in C. humilis, nor nearly equal to the length of the remaining portion of the plate." He also stated that C armstrongianus lacks the short form and the two posterior diagonal ridges of C. dalriensis Ether- idge, 1882, and he thought it was distinct from C. gemmatus de Koninck [=C. subgemmatus d'Orbigny, 1850], another coarsely granulate species from the Carboniferous of Belgium. Dunlop (1915) provided good photographs of what appear to be tail valves from Fife, in eastern Scotland. Later (1922), he said he thought the polyplacophoran fossils from the vicinity of Woodmill, Scotland, identified as Chiton gem- matus de Koninck ( 1 842), C cordatus Kirkby, 1859, and C armstrongianus Etheridge, 1882, were referable to a single species. Without careful study and comparison of available specimens, it would be premature to attempt to assign this material to a described genus and species. Gryphochiton Gray, 1847a would appear to be a possible generic allocation. arthurcooperi Smith, 1976, Pterochiton Pterochiton art hurcooperi Smith, 1976:281-285, fig. 1-28. Si- renko and Starobogatov 1977:36. Hoare and Smith 1984, fig. 7H-N. Geological Age. — Permian. Locality. — USA: Texas. Type locality: Road Canyon For- mation USNM loc. 703-c, Glass Mts., West Texas. Location of Material. — Holotype, USNM-211115; fig- ured paratypes, USNM-221 1 16-221 1 18, 221120-221124, 221 132. Valves from 30 other localities in USNM. Remarks. — Polyplacophoran of medium to large size when adult, based on a series of ex- tremely well preserved valves acid-etched from limestone blocks collected at or near the bound- ary between the Leonard and Word formations, Glass Mountain area, and the Cherry Canyon Formation, Guadalupe Series, Guadalupe Mountain area, West Texas. The head valves are somewhat more than semicircular in area; inter- mediate valves subquadrate, slightly longer than wide, the side-slopes forming an obtuse angle; tail valves elongate-ovate with prominent mu- cros, posteriorly placed. There are no distinctive sculptural features but the basic microsculpture of the tegmentum consists of extremely fine de- cussation on all valve areas. Ventrally, the artic- ulamentum lacks insertion plates but the sutural laminae on the intermediate and tail valves are large and well developed. Measurements of a full-grown head valve and of equivalent intermediate and tail valves are as follows (mm): Head Intermediate Tail Length Width Height 11.2 12.3 3.7 15.9 13.6 4.6 6.8 5.4 2.7 Most of the valves indicate the length of the an- imal in life to be 75-100 mm with all valves in place, excluding the girdle. Three unusually large valves have been collected; two of these are in- termediate valves measuring 27.5 mm and 23.5 mm respectively; the third is a very large tail valve measuring 25.0 mm long, 23.9 mm wide, and 5.5 mm high. These indicate that at least some animals achieved a total length of 1 50 mm or more without the girdle. This West Texas Permian polyplacophoran species belongs in the Neoloricata, suborder Lep- idopleurina, family Lepidopleuridae, based on its well-developed articulamentum, its lack of insertion plates, and the weakly-defined shell 14 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 areas of dorsal sculpture and configuration. The assignment of this species to the genus Ptero- chiton Carpenter in Dall, 1882 is based on the prominent, large-sized sutural laminae and ex- cavated anterolateral margins. Hoare and Smith (1984) illustrated preserved color markings on intermediate and tail valves of this species. ashbyi Bergenhayn, 1955. Genus incertae sedis Llandeilochiton ashbyi Bergenhayn, 1955:26-27, pi. 1, fig. 14 (type), pi. 2, fig. 12. Smith 1960:170-172, figs. 44,3a-b [ex Bergenhayn]. Geological Age. — Middle Ordovician (Llandeilo, Bal- clatchie). Locality.— South Scotland. Location of Material.— Type, BM (N.H.) 961. Remarks.— The species is based on a single intermediate valve, which is divided into seven separate shell areas— a most peculiar form for a polyplacophoran. Bergenhayn erected a new family for it (Llandeilochitonidae), the system- atic position being uncertain. So far as known, no additional material has been collected and the status of the species, even as a valid polyplacophoran, seems highly prob- lematical. australianus Iredale and Hull, 1926, Permochiton Permochiton australianus Iredale and Hull, 1926:326, pi. 45 [type species of Permochiton Iredale and Hull, 1926, by monotypy]. Iredale and Hull 1927:141, pi. 18. Ashby 1929: 227-228. Cotton and Godfrey 1940:569, 577, fig. 589. Cot- ton 1964:127, 140, fig. 139. Yochelson 1971: 130, 132. Van Belle 19756: 138, pi. 3, fig. 4. Sirenko and Starobogatov 1977: 35. Geological Age. — Permian (Upper marine series). Locality.— Australia: Permo-Carboniferous beds of Bun- adoon, New South Wales. Location of Material. — Holotype, a complete cast with two overlying pieces of matrix in Australian Museum, Sydney, Paleontological Section no. F.45764. Plastoholotype of cast in CAS- 128 17. Remarks.— A cast of the holotype, but not of the overlying pieces of matrix, was furnished through the courtesy of Dr. H. O. Fletcher of the Australian Museum. The specimen is entire with all eight valves in place and has the general aspect of a Recent species. The valves are gothic-arched with almost straight side-slopes that are swept- wing posteriorly; the jugal ridge is fairly sharp, being only slightly rounded along the median line. The head valve, though present, is not well preserved and is merged with valve ii in the fossil state. Intermediate valves appear to have fairly prominent, raised lateral areas and may have been mucronate in a living condition. Neither insertion plates nor sutural laminae are visible on the cast although Iredale and Hull's suppo- sition that they are present in this species is prob- ably correct. The cast of the tail valve has three subtriangular, low, rounded bosses radiating from the center of the posterior margin but this, of course, gives no indication of the external con- figuration of this valve. The sculpture of intermediate valve exteriors, based on the available pieces of overlying matrix, is a peculiar ribbed pattern, which is likened by Iredale and Hull to that found on species of Isch- nochiton or Lepidopleurus. This is difficult to in- fer from the drawings by Joyce K. Allan {in Ire- dale and Hull 1927, pi. 18). Any relationship to Lepidopleurus is certainly not indicated. Measurements of the cast of Permochiton aus- tralianus are: length, 17.5 mm; width, 10 mm; height, 6 mm. The angle of divergence appears to be a little less than 45°. Before the cast was available, it was doubtful that this fossil was a polyplacophoran. However, a study of the cast removes this doubt. Permo- chiton has been assigned to the Lepidopleuridae, suborder Cymatochitonina Sirenko and Staro- bogatov, 1977, and the family Permochitonidae Sirenko and Starobogatov, 1977. barrandeanus de Ryckholt, 1852. Genus incertae sedis Chiton barrandeanus de Ryckholt, 1852:65, fig. 37-38. de Koninck 1883:211. Rochebrune 1883:33. Chitonellus barrandeanus (de Ryckholt). Kirkby 1862:237. Young 1878:324. Geological Age. — Lower Carboniferous. Locality.— Belgium: Vise. Location of Material. — Unknown. Remarks.— The species is based on a single, heart-shaped valve, asymmetric in outline. De Koninck said it was not a polyplacophoran; Rochebrune believed it to be a species of crinoid. De Ryckholt's illustrations are stylized drawings. The valve has an unusual shape and its assign- ment to the Polyplacophora probably is incor- rect. SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 15 bennieanus Etheridge, 1882. Genus incertae sedis Chitonellus bennieanus Etheridge, 1882:99-100, pi. 2, fig. 11- 13. Geological Age. — Lower Carboniferous (Main or Hurlet Limestone). Locality. — Scotland: Ayrshire, Law Quarry, near Dairy. Location of Material. — Collections of J. Bennie, J. Arm- strong, J. Smith, etc. (fide Etheridge). Present location un- known. Remarks.— The valves described and illus- trated by Etheridge appear quite similar to those of Chitonellus patelliformis Etheridge ( 1 882) from the same general locality except for some dis- tortion during fossilization. They are not as markedly asymmetric in shape as C distortus Kirkby, 1859 from the British Permian, how- ever, and are slightly larger in size than valves of C. patelliformis, one of them measuring ap- proximately 3 mm long and slightly less in width. These peculiarly shaped and sculptured valves belong to a group of species described as poly- placophorans and first reported from the British Permian under the name Calyptraea antiqua Howse, 1848, and later named Chitonellus an- tiquus by Kirkby (1859). Other related species are mentioned above. Most authors have raised strong doubts that this group of fossils actually are polyplacophorans, having more of the char- acters of some type of patellid gastropod. bergenhayni Marek, 1962, Eochelodes Eochelodes bergenhayni Marek, 1962:373-375, pi. 1, text fig. 1. Van Belle 1975a: 124, pi. 1, fig. 2. Sirenko and Starobo- gatov 1977:31. Geological Age. — Middle Ordovician (Caradoc). Localities. — Europe: central Bohemia (Czechoslovakia). Type locality, Knizkouvice, near Zdice, lower part of the Cer- nin Beds. Other localities, Zdice and Zaluzi near Horovice. Location of Material. — Holotype in the collection of the Geological Survey of Czechoslovakia, Prague; paratypes in the same collection and in the Marek Collection. Remarks.— The valves are subtriangular with straight anterior margins and rounded apexes. They are small and apparently rather thin com- pared with valves assigned to the genus Chelodes. The holotype measures: length, 4.6 mm; width, 4.3 mm. The paratypes range in length from 2.4- 4.0 mm and in width from 2.5-3.6 mm. Thick- ness measurements and side-slope angles are not provided. The apical area covers nearly half the length of a valve, ventrally. The illustrations seem adequate except for the lack of side and end views of one or more of the valves. This species is properly assigned to the order Chelodina. However, the necessity or the desir- ability of creating a new family for it is doubtful, based on the evidence provided by Dr. Marek. A more conservative approach would be to allow his new genus Eochelodes to stand along with Chelodes Davidson and King, 1874, in the family Chelodidae. bergmani Davidson and King, 1874, Chelodes Chelodes bergmani Davidson and King, 1874:167-168, pi. 18, fig. 14, 14a-c [type species of Chelodes Davidson and King, 1 874, by original designation]. Lindstrom 1 884:5 1 , pi. 2, fig. 1-8. Fischer 1885:878. Etheridge 1897:68. Bergenhayn, 1943: 298 (as "bergmannr)\ 1955:12-13, pi. 1, fig. 3a-b, pi. 2, fig. 2 (reconstruction). Smith 1960:149-150, fig. 34,5a (recon- struction), 5b-c (type) [ex Bergenhayn 1955]. Van Belle 1975a: 123, pi. 1, fig. la-b. Sirenko and Starobogatov 1977:31, fig. la, b, 2a. Geological Age. — Middle Silurian (Gotlandian). Localities. — Sweden: Uppermost limestone of Klinteborg; oolite quarry near Gannvik, Grotlingbo (Lindstrom). Wen- lock, Gotland (Etheridge). Location of Material.— Types, RM-6027, 6028. Addi- tional specimens, RM-6025, 6030 (fide Bergenhayn 1955). Remarks.— This is the type species of Che- lodes Davidson and King, 1874 by original des- ignation. Bergenhayn's illustrations of the type show the massive construction of the valves of Chelodes, with the extensive apical area as seen from the ventral side, which is as long or longer than half the valve length. The anterior margins of intermediate valves are almost straight, com- pared with C. gotlandicus Lindstrom, 1884, in which they are strongly emarginated. Also in C gotlandicus the apical area is slightly shorter than half the valve length. birhombivalvis Bergenhayn, 1955, Gotlandochiton Gotlandochiton birhombivalvis Bergenhayn, 1955:18-19, pi. 1, fig. 7 (type); pi. 2, fig. 6 (reconstruction). Sirenko and Sta- robogatov 1977:31. Geological Age. — Middle Silurian (Gotlandian). Localities. — Sweden: Gotland, at Visby and Kalens Kvarn, Visby. Location of Material. — Holotype, RM-6031. Additional specimens, RM-6423, 6424. Remarks.— "This species is differentiated from all previously known paleoloricates by the fol- lowing combinations of characters: birhombic 16 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 form of the intermediate valves, + the extent of the jugal angle, + the complete coverage, + the complete lack of shell areas ... the species is assigned, with reservations, to the genus Gotlan- dochiton instead of to the genus Chelodes. It can- not be assigned to the latter because of the un- usual form of the valves and of the complete coverage" (Bergenhayn 1955:19). Measurements are as follows (mm): Specimen no. Length Width 603 1 (Holotype) 6023 7.4 13.0 12.5 12.0 and tail valves but only a tail valve was ade- quately figured by Kirkby and Young (1867). Kirkby had "a nearly perfect posterior plate and a fragment of an intermediate plate " He illustrated the tail valve, which has a semicircular posterior margin and a prominent, narrow mu- cro; the valve is sharply concave posteriorly. It measures: length, lh inch (13 mm); breadth, % inch (17 mm). Both specimens are worn and rather thick-shelled. Rochebrune doubted that it was a polypla- cophoran, believing that it showed the characters of Bathyurus Billings, a trilobite. Bergenhayn calculated the total length of all valves in place to be 48.9 mm for the holotype, and 84.4 mm for valve no. 6023. bohemicus (Barrande, 1867), Chelodes Chiton bohemicus Barrande, 1867:175, pi. 16, fig. 19-28b. Bergenhayn 1930:15. Chelodes bohemicus (Barrande). Lindstrom 1884:48. Ether- idge 1897:68. Bergenhayn 1930:15. Horny in Spinar 1965: 319, fig. VIII-8. Helminthochiton bohemicus (Barrande). Robson 1913:304. Geological Age. — Upper Silurian. Locality. — Bohemia: Between Bubowitz and Lodenitz. Location of Material. — Unknown. Remarks.— There seems little doubt about the correctness of the assignment of this species to the genus Chelodesby Lindstrom in spite of Rob- son's later assignment of the species to the genus Helminthochiton. burwwianus Kirkby ', 1862, "Chiton" Chiton burwwianus Kirkby. Baily 1860:95 and footnote; a nomen nudum. Kirkby 1862:234, fig. 1-2. Kirkby and Young 1867:340, pi. 16, fig. 14-15. Rochebrune 1883:35 (as "bur- rovianus"). Geological Age. — Lower Carboniferous (Lower Scar Limestone). Locality. — England: Settle, Yorkshire, near the base of the Lower Scar subdivision of the Mountain Limestone (Kirkby); Williamswood (Rochebrune). Location of Material. — Unknown. Remarks.— Baily (1860) said that J. H. Bur- row found the valves of four or five species at Settle, Yorkshire; Kirkby applied the name bur- wwianus to only one of these species. It was described formally by Kirkby (1862). The species is predicated on both intermediate calathicolus Smith in Smith and Toomey, 1964, Ivoechiton Ivoechiton calathicolus Smith in Smith and Toomey, 1 964:24- 25, pi. 5, fig. 1-14. Geological Age. — Lower Ordovician (Kindblade Forma- tion). Localities.— USA: Oklahoma, type lot from the lower part of the Kindblade Formation, Mill Creek section, Arbuckle Mts.; also from Joins Ranch section, same formation, in a zone of abundant Calathium, 485 feet above the base of the Kind- blade. Location of Material. — Holotype, OU-5213; paratypes OU-5214-5216; paratypes, USNM-144536-144539; para- types, CAS-12589-12591. Remarks.— The type lot contains ten inter- mediate valves. No end valves were recovered from acid-etched limestone blocks. Diagnostic characters of the species include a rather blunt jugal ridge, with a pointed, slightly projecting apex, more or less straight side-slopes, semicir- cular side-margins, a V-shaped posterior edge view compared with an anterior edge view that is U-shaped, a strong ventral thickening, and a well-developed apical area. This species is most closely related to Ivoechiton oklahomensis Smith in Smith and Toomey, 1 964 from the same for- mation and locality. calceoloides Etheridge, 1897, Chelodes Chelodes calceoloides Etheridge, 1897:67-70, fig. A-F. Che/odes'? calceoloides Etheridge. Ashby 1 929:227. Iredale and Hull 1926:324; 1927:139. Cotton and Godfrey 1940:569 (as "Cheloides"). Cotton 1964:1 19 (as "Cheloides"). Geological Age. — Upper Silurian. Locality.— Australia: New South Wales, Portion 1 of 635 acres. Parish of Derrengullen, County King (Yass District). Location of Material.— Australian Museum, Sydney, Pa- leontological Section, type nos. 46739 and 46740. Plastotypes in CAS- 128 18, 12818a. SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 17 Remarks. — Although Australian specialists have generally agreed that this species is not a polyplacophoran, or at best a doubtful one, plas- totypes of the two valves on which the species is based, supplied through the courtesy of Dr. H. O. Fletcher of the Australian Museum, confirm Etheridge's allocation to the genus Chelodes. From the casts at hand, the two specimens both appear to represent intermediate valves, one (no. 46739) being more broadly alate with a somewhat less pointed apex than the other. In both specimens the jugal ridge is convex (more so in no. 46740) and rounded. The posterior apex of no. 46740 forms a blunt point but is incom- plete in no. 46739. Both valves have a rather shallow embayment in the anterior margin, sim- ilar but less pronounced than in Chelodes got- landicus Lindstrom, 1 884 from Sweden. No dor- sal sculpture or growth ridges are evident in either cast. Measurements of the casts are as follows (mm): No. No. Item 46739 46740 Length, overall 33.1 + 34.8 Length of jugal ridge along median line 30.5 34.6 Length (max.) of apical area 15.0 + 13.5 Width (max.) 25.3 21* Height (max.) 16.4 16.5 Thickness (max.) 10.0 9.8 Jugal angle (measured vertically) 85° 62° Approx. apical angle (measured hori- zontally) 43° 45° * Right anterior margin incomplete on one side. Chelodes calceoloides is by far the largest species in the genus discovered so far. Based on valve no. 46739, the living animal, exclusive of the girdle, would be approximately 201 mm long (almost 8 inches) by Bergenhayn's formula (1955: 1 1). This is nearly twice the length of C. berg- mani Davidson and King, 1874 (105 mm) and of C gotlandicus Lindstrom, 1884 (102 mm). The smallest described member of the genus is C. sellaeformis (Butts, 1926), which would have been 56 mm long by the same formula. canadense Clarke, 1907, Probolaeuml Probolaeuml canadense Clarke, 1907:194-195, text figs, (un- numbered). Geological Age. — Lower Devonian (St. Alban beds). Locality.— Canada: Cape Rosier Cove, Quebec. Location of Material. — Unknown. Remarks.— Clarke thought there was a note- worthy similarity in the form and aspect of his species to Chiton sagittalis Sandberger and Sandberger, 1856 from the Middle Devonian of Germany in the Stringocephalen Kalk, which has been rejected as a polyplacophoran herein. Pro- bolaeuml canadense appears to be a solid poly- placophoran and is probably a paleoloricate. canadensis (Billings, 1865), Priscochiton Chiton canadensis Billings, 1865:394, fig. 37a-c. Rochebrune 1883:19. Priscochiton canadensis (Billings). Dall 1882:281 [type species of Priscochiton Dall, 1882, by original designation]. Tryon 1883:339, pi. 85, fig. 64-66. Robson 1913:304. Shimerand Shrock 1944:526, pi. 216, fig. 6-8. Wilson 1951:16, pi. 1, fig. 1-3. Moore, Lalicker, and Fischer 1952:272, fig. 2a-c. Smith 1960:154, fig. 36,10a-c [ex Wilson]. Smith in Smith and Toomey 1964:14. Geological Age. — Middle Ordovician (Llandeilan). Locality.— Canada: Ontario-Quebec, in the Black River Limestone, Pauquette Rapids, Ottawa River. Location of Material.— National Museum of Canada, Ot- tawa. Remarks.— This species is based on Billings's original material, no other valves having been reported as collected since. Dall (1882) made it the type species of his genus Priscochiton, by original designation. Although Rochebrune (1883) doubted that Priscochiton canadensis was actually a polypla- cophoran, guessing it to be more closely related to Metapoma (a patellid gastropod), Wilson's (1951) excellent illustrations leave little doubt that the species is a polyplacophoran of a rather unique form. The two known valves appear to represent head valves rather than tail valves as assumed by Billings (1865). cancellus, DeBrock, Hoare, and Mapes, 1 984, Pileochiton Pileochiton cancellus DeBrock, Hoare, and Mapes, 1984:1125, fig. 2E, F, 5 A-T [type species of Pileochiton DeBrock, Hoare, and Mapes, 1984, by original designation]. Geological Age. — Middle Pennsylvanian (Desmoinesian). Locality. — USA: Texas, Lazy Bend Formation exposed on a small tributary to Kickapoo Creek, 30 m N of where Farm to Market Road 1 189 crosses Rocky Branch, approx. 8.5 km NE of Lipan and 0.75 km S of Kickapoo Falls, Hood Co. Dennis 7'/2-minute Quadrangle. Location of Material. — Holotype, OSU-36197; para- types, OSU-35993-36001, 36198-36200 and BGSU-4225. 18 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 Remarks.— A reconstructed specimen has a length to width ratio of approximately 2:1. The head valves are twice as wide as long with a straight or invaginated posterior margin, steep and straight slopes, and a large apical area. The intermediate valves are more than twice as wide as long, subrectangular in shape (apical angle av- erages 1 43°), with distinct central and lateral areas, sutural laminae are short and broad, with a large apical area. The tail valves are wider than long, broadly V-shaped in plan view, with steep slopes, mucro located posterior to midlength, jugal sinus sometimes present, and distinct central and pos- terior areas. Surfaces of the valves are orna- mented with large granules arranged in rows ex- cept in central areas where ridges paralleling the anterior margin are separated by granules form- ing a lattice pattern. Average dimensions are (mm): Head Intermediate Tail Length Width Height 1.6 4.0 1.8 2.7 5.3 1.9 1.6 2.3 1.1 The new genus Pileochiton was erected to in- clude taxa with steep-sloped head valves; inter- mediate and tail valves with distinct lateral and central areas where the ornamentation is differ- entiated; and tail valves having a near posterior mucro, being V-shaped, and with short and broad sutural laminae. carbonarius (Stevens, 1858), Glaphurochiton Chiton carbonarius Stevens, 1858:264. Meek and Worthen 1873:608, pi. 29, fig. 15. Collett 1879:327. Whitfield 1882: 96. Kindle 1898:468. Shimer and Shrock 1944:527, pi. 216, fig. 27-34. Anthrocochiton carbonarius (Stevens). Rochebrune 1883: 29- 30. Glaphurochiton carbonarius (Stevens). Raymond 1 9 10: 1 53, pi. 26, fig. 6; pi. 28, fig. 15-16 [type species of Glaphurochiton Raymond, 1910, by original designation]. Raymond 1911: 88-90, 96, pi. 5, fig. 4. Wanless 1958:21, 39. Yochelson and Saunders 1967:12. Sirenko and Starobogatov 1977:36, fig. lk-1. [non] Pterochiton concinnus (Richardson, 1956). Hoare, Stur- geon, and Hoare 1972:675. Pterochiton carbonarius (Stevens). Hoare, Sturgeon, and Hoare 1972:677-678, pi. 1, fig. 2-3; pi. 2, fig. 3-6. Hoare 1975: 223-224, fig. 1-3. Hoare and Sturgeon 1979:178-179, pi. 2, fig. 12-13 (not fig. 7-9); pi. 3, fig. 5-6. Hoare, Mapes, and Atwater 1983:999-1000, fig. 5L-M. Kues 1983:19-22, fig. 1. Geological Age. — Pennsylvanian. Localities. — USA: Illinois, Danville, roof of the Danville coal seam (Stevens); Missouri, St. Louis outlier, Labette Shale Member near top, Henrietta Formation (J. B. Knight, coll., Shimer and Shrock); Pennsylvania, Ames, and Pine Creek limestones, Allegheny Series (Raymond); Ohio, Putnam Hill Limestone and Vanport Limestone units, Lower Allegheny to Middle Conemaugh (Hoare, Sturgeon, and Hoare); Oklahoma, Gene Autry Formation and Texas, Smithwick Formation (Hoare, Mapes, and Atwater). Location of Material.— The whereabouts of Stevens's original specimens are unknown. Examples are in a number of paleontological collections, including the USNM, BM (N.H.), OSU, and BGSU. Hoare (1975) has selected a neotype for Chiton carbonarius after a search for type material proved fruitless. This is deposited in the Field Museum of Natural History, Chicago, Illinois, as UC-57331. It is a well-described and illustrated tail valve from or close to the type locality. Remarks. —This species seems to be relatively abundant and widespread geographically. Al- though Raymond (1910) designated it as the type species of a new genus Glaphurochiton, and Richardson (1956) placed it in Helminthochiton, this species has been placed in the genus Ptero- chiton Carpenter in Dall, 1882 by Hoare, Stur- geon, and Hoare (1972), Hoare (1975), Hoare and Sturgeon (1979), and Hoare, Mapes, and At- water (1983) in recent years. Sirenko and Sta- robogatov (1977) reassigned it to Glaphurochi- ton, with which we now agree, on the basis of the lack of excavated anterolateral margins on the intermediate and tail valves, more extensive apical areas, narrower and less exposed sutural laminae and the lack of a jugal sinus. Raymond (1911) reported Glaphurochiton carbonarius from Stoops Ferry, Pennsylvania (Pine Creek Limestone), and from Summerhill, Pennsylvania, in a small cut on the Pennsylvania Railroad, 88 miles east of Pittsburgh; he also recorded it at Pittsburgh in a cut on the Brilliant Cutoff of the Pennsylvania Railroad, near the Brilliant pumping station (Ames Limestone). A beautifully preserved tail valve of Glaphu- rochiton carbonarius, in the collection of the USNM, no. 27750, measures: length, 9.6 mm; width, 8.3 mm; height ca. 4 mm. A 35-mm color slide of this valve is in the CAS Color Slide Se- ries, No. 2298. One of the broadly rounded su- tural laminae is well preserved on this specimen, and the irregularly scattered, round to somewhat elongate, pustular, dorsal sculpture, together with at least one rather prominent ridge that parallels the posterior valve margin is well shown. The USNM also contains two separate series of valves from Missouri, near the top of the Labette Shale Member, Henrietta Formation, St. Louis, Mo. SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 19 outlier, collected by J. Brooks Knight, which have been correctly identified as "Chiton" carbonarius by Shimer and Shrock (1944). Several specimens have at least two adjacent valves in place in the matrix; both end and intermediate valves are well represented. The coarse pustulation of G. carbonarius shows up well on many of the valves. The following measurements of selected valves from Knight's "Loc. 43 'red' " give a good idea of valve sizes (mm): Dimension Head Intermediate Tail Length Width Height 14.5 14.5 8.0 14.9 16.3 + 5.2 17.5 15.1 4.0 Hoare, Sturgeon, and Hoare (1972) reported extensive collections of valves of this species in Ohio and provided measurements and excellent illustrations of some of them. Also, they fur- nished valuable new information on the micro- structure of the valves and discussed the paleon- tology of the species (see pp. 676-677). They originally considered Helminthochiton concin- nus Richardson (1956) to be a synonym, as in- dicated above, but we now accept it as a distinct species. coarctatus (de Koninck, 1883) Helminthochiton coarctatus de Koninck, 1883:201-202, pi. 50, fig. 33-36. See: priscus Miinster (1839). Geological Age.— Lower Carboniferous. Locality. — Belgium: Tournai. Location of Material. — Location of type specimens un- known. A series of valves is in the USNM-63401. Remarks. — Specimens in the United States National Museum are labeled: "Helminthochi- ton coarctatus, de Kon./ Carb - Kohlen Kalk / Tournai / Belg." on the reverse side of an original label headed: "Comptoir Beige de Mineralogie & de Paleontologie." They consist of a set of valves presumed to be in positions i-v, inclusive, which have been glued in what might be consid- ered as a normally overlapping series; and a sim- ilar, continuing series of valves vi-viii. All valves are well preserved and complete except for the one presumed to be valve vi, which is broken. The head valve is roughly semicircular in shape and measures 13 mm in width and 8.8 mm in length. The intermediate valves are slightly swept- wing in shape and straight-sided with acute jugal ridges terminating in sharply-pointed, slightly mucronate apexes. The divergence of the side- slopes is about 90°. The tail valve is somewhat more than semicircular in dorsal aspect with a well-marked, small, broadly triangular, jugal area terminating in a posteriorly placed, low, pointed mucro. It is 14.4 mm wide and 13 mm long, the point of the mucro being only 2.5 mm from the posterior margin. The jugal area behind the mu- cro is depressed with a slight upturn toward the posterior end. None of the valves show any vestiges of mi- crosculpture. All of them are marked with one to three fairly prominent parallel ridges following the configuration of the side margins and, in ad- dition, the tail valve has some curving striations in the depressed area surrounding the point of the mucro. Sutural laminae of the intermediate valves are rather small, rounded and somewhat thickened; the sutural sinuses between them are wide and only slightly curved. There appear to be hardly any marked specific differences between Gryphochiton coarctatus and G. priscus (Miinster, 1839). Consequently, for the present at least, the former should be treated as a synonym of the latter, well-known species. collinensis Gortani, 1913, "Chiton" Chiton collinensis Gortani, 1913:262, fig. 13a-b. Geological Age. — Lower Devonian ("Neodevonico infe- riore"). Locality. — Austria: Nella Giogaia del Coglians. Location of Material. — Unknown. Remarks. — The specimen on which this species is based is elliptical in outline and mea- sures: length, 17 mm; width, 1 1 mm; and height, 6 mm. The angle of divergence of the side-slopes is 1 10°. Gortani thought it was a head valve and compared it with the head valve of Chiton lae- vigatus Roemer, 1855 and Chiton injlatus Trenkner, 1868 from the Lower Devonian of the Hartz Mts., Germany. The diagnosis of Chiton collinensis is not suf- ficiently definitive and the illustrations of the valve are too poor even to guess at its systematic position. coloratus (Kirkby, 1862), "Chiton" Chiton coloratus Kirkby, 1862:234-235, fig. 3-6. Kirkby and Young 1867:340, pi. 16, fig. 8a-b. Rochebrune 1883:33. Rhombichiton coloratus (Kirkby). de Koninck 1883:209, pi. 52, fig. 39-42. 20 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 Geological Age. — Lower Carboniferous (Lower Scar). Locality. — England: Yorkshire, in the Mountain Lime- stone (Kirkby); Settle, Yorkshire (Rochebrune). Location of Material.— Unknown. Remarks. — Kirkby based this species on an intermediate and a tail valve. The former mea- sures 0.6 inch (17 mm) long and 0.5 inch (13 mm) wide. It is subquadrate in shape, the side- margins concave and trending inward posterior- ly. No mention is made of sutural laminae and Kirkby's illustration does not show any. The col- or of the dorsal area and the anterior portion is black, following the contour of the margin and the raised dorsal area. The tail valve has much the same aspect as that of Chiton burrowianus Kirkby, 1862 from the same locality. Of interest is Kirkby's remark on coloration. He says: ". . . the color is very evident; the un- colored surface is grey, which is the tint of the matrix. That this is truly the remains of the orig- inal color I can scarcely doubt, considering the symmetry observed in its arrangement, which cannot be ascribed to the accidents of fossiliza- tion." Kirkby and Young (1867) mention the collec- tion of a head valve and several tail valves. Rochebrune (1883), whose guesses generally were unreliable, did not believe it was a polyplaco- phoran. comptus, Hoare and Smith, 1984, Ochmazochiton Ochmazochiton comptus Hoare and Smith, 1984:87-90, fig. 2 (reconstruction), 3A-S [type species of Ochmazochiton Hoare and Smith, 1984, by original designation]. Geological Age. — Lower and Middle Permian (Wolfcam- pian, Leonardian). Localities. — USA: Texas, Bone Spring Formation, USNM Iocs. 725c and 725d; Road Canyon Formation, USNM loc. 72 lj; Cathedral Mountain Formation, USNM loc. 72 lu, Glass Mts., West Texas. Location of Material. — Holotype, USNM-330834; para- types, USNM-330835-330847. Remarks.— A reconstructed specimen mea- sured approximately 76 mm in length and 40 mm in width with a length to width ratio of 1 .9: 1 . The head valves are twice as wide as long with an invaginated posterior margin and a short in- sertion plate marked by grooves and/or rough slits. The intermediate valves are low-arched and swept-winged with a prominent apex (apical an- gle averages 124°), and much wider than long. The side-slopes and posterior margins are con- cave and lateral and central areas are distinct. The sutural laminae are short and broad, ex- tending onto the lateral margins as insertion plates, being cut by 3-4 slits. The tail valves are high, wider than long, with an elevated mucro anterior to midlength at the end of a short jugal area. The side-slopes are flat with narrow lateral areas set off from the posterior area by changes in ornamentation. The sutural laminae are not preserved but a short insertion plate is present marked by numerous grooves and/or slits. Or- namentation consists of closely spaced, nodose ridges curving across the central areas and be- coming sinuous on the lateral areas. Average dimensions are (mm): Head Intermediate Tail Length Width Height 8.6 4.2 4.6 8.5 20.0 7.2 6.8 4.8 3.5 The new genus Ochmazochiton and new fam- ily Ochmazochitonidae were erected by Hoare and Smith (1984) to include those taxa bearing slitted, but still primitive, insertion plates and having distinct central, lateral, and posterior areas on the valves. Ochmazochitonidae is believed to be a synonym of Heterochitonidae Van Belle, 1978. Lobarochiton Hoare, 1976 may belong to this family, although only the tail valve is known. concentricus (de Koninck, 1844), Pterochitonl Chiton concentricus de Koninck, 1 844:322-323, pi. 22, fig. 4a- d. de Ryckholt 1845:62. Bronn 1848:291. d'Orbigny 1850, vol. 1:127. de Koninck 1857:195. Baily 1859:333; 1860:95. Rochebrune 1883:31. Helminthochitonl concentricus (de Koninck). Salter 1847:49, 52. Rhombichiton concentricus (de Koninck). de Koninck 1883: 210, pi. 52, fig. 34-38. Pterochiton (Loricites) concentricus (de Koninck). Dall 1882: 281 [type of the subgenus Loricites Carpenter in Dall, 1882, by original designation]. Loricites concentricus (de Koninck). Tryon 1883:339. Fischer 1957:13. Geological Age. — Lower Carboniferous. Locality. — Belgium: Vise. Location of Material. — Figured type, PSM (de Koninck Collection) (fide P.-H. Fischer). Specimens in BM (N.H.) (fide H. W. Ball). Remarks.— According to de Koninck (1844) this is a small species, the single intermediate valve collected being not more than 8 mm long, SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 21 somewhat reniform in shape, subcarinate along the jugum, the dorsal surface decorated with reg- ularly spaced, concentric sulcations. Until more study can be given to available specimens of this species, it should probably be left in the genus Pterochiton pending a more ac- curate systematic assignment, should such be deemed necessary. concinnus (Richardson, 1956), Glaphurochiton Helminthochiton concinnus Richardson, 1956:62, fig. 34-36. Smith 1960:148, fig. 33,la-c (ex Richardson). Yochelson and Saunders 1967:12. Pterochiton concinnus (Richardson). Hoare, Sturgeon, and Hoare 1972:675. Yochelson and Richardson 1979:321-331, fig. 1-5. Glaphurochiton concinnus (Richardson). Sirenko and Staro- bogatov 1977:36. Geological Age. — Middle Pennsylvanian (Desmoinesian). Locality.— USA: Illinois, Francis Creek Shale, Mazon Creek area, near Coal City. Location of Material. — Holotype, 3000- 1 . 1 in the private collection of Mr. and Mrs. John M. McLuckie, Coal City, Illinois (fide Richardson). Plastotypes and additional speci- mens (PE 31877-31878, 31904, 31946-31947), are in the re- positories of the Field Museum of Natural History and in Princeton University. Remarks.— This species is based on remark- ably well preserved specimens preserved in iron- stone concretions. Many specimens have all eight valves in place with an impression of the radula below valves i and ii, making them unique in the fossil polyplacophoran record (Richardson 1956, fig. 34, 36; Hoare and Sturgeon 1979, pi. 2, fig. 7-9; Yochelson and Richardson 1979, fig. 1-4). In other specimens, well-developed sutural laminae and the granular sculpture of the teg- mentum, which is characteristic of the genus Gla- phurochiton, is beautifully preserved. Yochelson and Richardson (1 979) describe and illustrate the outline of the girdle and the distribution of the spicules (fig. 3, 5). Richardson says Glaphurochiton concinnus is half the size of G. carbonarius (Stevens, 1858), a fossil species of approximately the same age from Danville, Illinois. Hoare, Sturgeon, and Hoare (1972:675) considered G. concinnus to be a junior synonym of G. carbonarius. A compar- ison of latex casts of G. concinnus with G. car- bonarius indicates that the two species are dis- tinct with a finer ornamentation on the former species as well as a more rounded margin on the tail valve. The assignment to Glaphurochiton Raymond, 1 9 1 0 is on the same basis as discussed under G. carbonarius. cooperi Bergenhayn, 1960, Preacanthochiton Preacanthochiton cooperi Bergenhayn, 1955:39 (nomen nu- dum); 1960:169-173, fig. 1-3 [type-species of Preacantho- chiton Bergenhayn, 1960, by original designation]. Smith in Smith and Toomey 1964:15. Runnegar and Pojeta 1974: 312-313. Runnegar, Pojeta, Taylor, and Collins 1 979: 1391- 1392, pi. 2, fig. 62-66. Geological Age. — Upper Cambrian (Eminence Dolomite). Lower Ordovician (Gasconade Formation). Localities. — USA: Missouri, Shannon, Washington, and Crawford counties (Upper Cambrian); Reynolds and Madison counties (Lower Ordovician). Locality details are provided by Bergenhayn (1960:169). Location of Material. — Holotype, USNM- 137370. A to- tal of 38 specimens from the Upper Cambrian and four from the Lower Ordovician are also in the USNM. Remarks.— The species is based on presumed head, tail, and intermediate valves, which are of small size. Bergenhayn estimated that the holo- type was a polyplacophoran about 3 1 mm long, exclusive of the girdle, its length being about seven times its width. Another specimen is es- timated to have been about 38 mm long. A new family, Preacanthochitonidae, as well as a new genus is erected for Preacanthochiton cooperi and for another species, P. depressus, described at the same time. Following a critical examination of the holo- type and related specimens Smith was unable to confirm the fact that the fossils represented poly- placophorans, appearing to be more patellid in aspect. Runnegar and Pojeta (1974) said: ". . . Preacanthochiton appears to be closely related to the Early Ordovician genus Chelodes David- son and King." Later, Runnegar et al. (1979) redescribed and illustrated the type specimens, accepting them as part of the earliest polypla- cophoran faunas from the Late Cambrian. Therefore, the family Preacanthochitonidae, the genus Preacanthochiton, and the species P. cooperi and P. depressus are being accepted as valid constituents of the Paleozoic polyplacoph- oran fauna for the purpose of this report. aff. cooperi Bergenhayn, 1 960, Preacanthochiton Preacanthochiton aff. cooperi Bergenhayn, 1960:173-174, fig. 9-10. Geological Age. — Upper Cambrian (Eminence Dolomite). 22 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 Localities.— USA: Missouri, Shannon and Franklin coun- ties. Location of Material. — Hypotype, USNM-137374. Remarks.— The fossils consist of a cast of a tail valve and three other presumed tail valves from several field localities. The comments on related specimens of Pre- acanthochiton cooperi Bergenhayn (1960) apply to these specimens also. cordatus (Kirkby, 1859), Lekiskochiton? Chiton! cordatus Kirkby , 1859:6 16-6 17, pi. 16, fig. 24-27, 54- 55. Baily 1859:333; 1860:95. Kirkby 1860:250-252, pi. 13, fig. 24-27. Geinitz 186 1:55, fig. VII- 10, 11. Kirkby and Young 1867:341, pi. 16, fig. 10, lla-b. Dall 1882:283. Lindstrom 1884:49. Branson 1948:760. Yochelson 1971:130. Chitonellus cordatus (Kirkby). Rochebrune 1883:40-41. Geological Age. — Permian. Locality. — England: Durham. Found rarely in the shell limestone of Tunstall Hill (Kirkby). Upper Zechstein magne- sian limestone (Rochebrune). Location of Material. — Unknown. Remarks. — From Kirkby's illustrations it is difficult to tell whether the fossils represent poly- placophorans or not, although some have a poly- placophoran aspect. Geinitz, Dall, Rochebrune, Lindstrom, and Branson all thought these fossils were doubtful polyplacophorans. The so-called valves are small, not being more than 3-4 mm in length and width. Kirkby's figures 24 and 27, which he thought were tail valves, have ques- tionable polyplacophoran aspects and do not ap- pear to represent the same species as his figures 25-26, said to be intermediate valves, which do appear polyplacophoran. Figures 54 and 55 are considered to be a head valve, which also seems polyplacophoran. If Chiton cordatus is based upon the plates illustrated in figures 25-26 the species can be accepted as a valid polyplacoph- oran and can be tentatively assigned to the genus Lekiskochiton Hoare and Smith (1984:93) from the Permian of West Texas. Lekiskochiton? cordatus (Kirkby, 1859), a Permian species, is not Chiton? cordatus Kirkby and Young, 1867 from the Carboniferous Lower Scar Limestone of Yorkshire, England. The dis- cussion under this species name by Etheridge (1882) refers to valves from the Carboniferous which are different than the Carboniferous valves of Kirkby and Young (1867) which were re- named Rhombichiton acutivalvis de Koninck, 1883, q.v. cordatus (Kirkby and Young, 1867) Chiton! cordatus? Kirkby and Young, 1867:341, pi. 16, fig. 10, lla-b. See: acutivalvis de Koninck, 1883. cordifer (de Koninck, 1 844), Glyptochiton Chiton? cordifer de Koninck, 1844:324, pi. 22, fig. 5a-b. de Ryckholt 1845:60, pi. 4, fig. 9-16. Salter 1847:49. Bronn 1848:291. Bigsby 1878:319. Dall 1882:283. Rochebrune 1883:31-32. Chiton (Chitonellus) cordifer de Koninck. de Koninck 1857: 196 (as "condifer"). Baily 1859:333; 1860:170. Chitonellus cordifer (de Koninck). d'Orbigny 1850, vol. 1:127. Kirkby 1862:237 (footnote). Etheridge 1882:97. Glyptochiton cordifer (de Koninck). de Koninck 1883:213 [type species of Glyptochiton de Koninck, by original designation]. Quenstedt 1932:95-96. Fischer 1957:12. Smith 1960:172, fig. 44,5a-c [ex de Koninck 1883]; 1971:567-572, fig. 1-15 (on 2 pis.). Van Belle 19756:143, pi. 2, fig. 3a-c. Sirenko and Starobogatov 1977:37. Geological Age.— Lower Carboniferous. Locality. — Belgium: Tournai. Location of Material. — Four specimens, PSM (de Ko- ninck Collection) (fide P.-H. Fischer); BM (N.H.) (fide H. W. Ball). USNM-63404 (six specimens: head, tail, and four in- termediate valves). Remarks.— The intermediate valves are elon- gate, with deep sinuses at both ends and a heart- shaped or teardrop-shaped tegmentum. They are unlike the fossil valves of any other genus of Paleozoic or Mesozoic polyplacophorans so far described. Other representatives of the genus Glyptochiton are G. youngianus Kirkby in Young, 1865 and G. subquadratus Kirkby and Young, 1867. The early illustrations of Glyptochiton species are highly stylized drawings. Better illus- trations of specimens in the USNM were sup- plied by Smith (1971); these show the presence of a well-developed pectinated insertion plate on the tail valve and pectination of the ventral sur- face under the tegmentum layer at the posterior sinus. Earlier paleontologists had considerable doubt whether Glyptochiton cordifer was, in fact, a polyplacophoran. De Ryckholt thought it might be a crinoid plate and so did Rochebrune and Dall. According to Salter (1847), even de Ko- ninck admitted that it might be an "encrinital plate," although he considered it to be polypla- cophoran in 1883 when he established the genus Glyptochiton for it. There now seems little doubt that Glyptochiton is a polyplacophoran of an unusual kind. The tegmentum of the valves is similar to that in the SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 23 Recent genus Amicula in which the valves are buried deeply in its thick, muscular girdle with only a small area of heart-shaped tegmentum exposed. The valves of the Recent genus Chori- plax are somewhat similar in this respect. Starobogatov and Sirenko (1975) proposed a new suborder Choriplacina and a new family Glyptochitonidae for the genus Glyptochiton. cordiformis Sandberger, 1845, "Chiton" Chiton cordiformis Sandberger, 1845:439. Bronn 1848:291. Pictet 1 855:300. deKoninck 1857:192, 196.Baily 1859:333. Baily 1860:92, 95. Rochebrune 1883:23. de Koninck 1883: 199. Geological Age. — Middle Devonian. Locality.— Germany: Vilmar, in Prussia (Hesse-Nassau) (Sandberger); Grand, Hartz Mts. (Roemer). Location of Material.— Unknown. Remarks.— This species name was introduced by Fridolin Sandberger, Guido Sandberger' s younger brother, for specimens identified and illustrated as Bellerophon expansus Sowerby, 1839 by Roemer (1843:32, pi. 9, fig. 5). Bronn ( 1 848) listed B. expansus as a synonym of Chiton cordiformis probably based on Roemer's mate- rial. Pictet (1855) expressed the view that these fossils were polyplacophoran plates, at the same time pointing out the possibility of confusion between polyplacophoran tail valves and the shells of Metapoma, a patellid gastropod. De Koninck (1857) and Baily (1860) listed C cor- diformis under a single species number along with Chiton corrugatus Sandberger and Sandberger ( 1 856), C priscus Sandberger (1842) [non Miins- ter, 1839], and C. sandbergianus de Ryckholt, 1845, evidently considering the three conspecif- ic. Referring to C. subgranosus and C fasciatus, both of Sandberger (1842), de Koninck said that "one of these species is probably identical with that which Roemer has mistaken for Bellerophon expansus Sow." He did not specify which one, however. To further complicate the synonymy of C cordiformis it should be noted that Clarke (1885) placed it under C laevigatus Roemer, 1855. Both C subgranosus and C. fasciatus were nomina nuda at the time the names were intro- duced; both names were dropped and replaced by C. corrugatus and C sagittalis by the Sand- bergers in 1856. Thus the validity of C. cordi- formis and its relationship to other species from the Devonian of Vilmar remains in doubt. Roemer's illustration of" Bellerophon'''' expan- sus shows an intermediate valve of swept-wing shape with a deep anterior sinus and no sutural laminae or insertion plates. This is the only spec- imen, apparently. Roemer's identification as a Bellerophon is manifestly incorrect. If it can be established that Chiton cordiformis has no artic- ulamentum shell layer, it belongs in the suborder Chelodina. The taxonomic status of this species can be determined only by a further study and comparison of type and related specimens with other species from the Devonian of Vilmar. corrugata Bischoff, 1981, Cobcrephora Cobcrephora corrugata Bischoff, 1981:192-193, pi. 2, fig. 31- 33. Geological Age. — Middle Silurian. Localities. — Australia. Quarry Creek Limestone (type sec- tion) on south bank of Quarry Creek, about 2 1 km west of Orange, New South Wales. Boree Creek Formation, 1 km west of Borenore Caves, approximately 22 km west northwest of Orange, New South Wales. Location of Material. — Holotype (SMF-34370) and para- types (also listed as SMF-34370) deposited in the Senckenberg Museum, Frankfurt am Main, Republic of West Germany. Remarks.— Valves of alternating lamellae of organic and apatitic material. Tail and head valves unknown. Intermediate valves similar to Cobcrephora silurica Bischoff, 1 98 1 but differ by having more pronounced jugal ridges separating a deeper trough with well-developed transverse ridges on the lateropleural areas. corrugatus (Sandberger and Sandberger, 1856), Probolaeum Chiton subgranosus Sandberger, 1 842:399 (nomen nudum), de Ryckholt 1845:62. Salter 1847:49, 51 (footnote). Bronn 1848: 292. de Koninck 1857:192 (and footnote). Baily 1859:333; 1860:92 (and footnote). Chiton corrugatus Sandberger and Sandberger, 1856:238-239, pi. 26, fig. 22, 22a-d [non Reeve (1848), a Recent species], de Koninck 1857:192 (and footnote), 196. Baily 1859:333; 1860:92 (footnote), 95. Trenkner 1868:136-137, pi. 2, fig. 29. Dall 1882:283 (for Sandberger and Sandberger 1856, pi. 26, fig. 22a only). Clarke 1885:338-339. Chiton symmetricus Trenkner, 1868:137, pi. 2, fig. 30 [fide Clarke 1885]. Gryphochiton corrugatus (Sandberger and Sandberger). Roche- brune 1883:21-22. Probolaeum corrugatum (Sandberger and Sandberger). Dall 1882:281-282 [type species of Probolaeum Carpenter, in part, Chiton corrugatus Sandberger and Sandberger, by orig- inal designation]. Tryon 1883:339. Smith 1960:154, fig. 36,8 [ex Sandberger and Sandberger]. Geological Age. — Devonian, in Stringocephalen Kalk (Sandberger and Sandberger). Middle Devonian (Rochebrune). Devonian and Lower Devonian (Dall). 24 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 Locality.— Germany: Vilmar, in Prussia (Hesse-Nassau) (12.9 km SW of Weilberg on modern maps) (Sandberger and Sandberger); Ehrenbreitstein (Dall). Location and Material. — Location of type specimens un- known. The Sandbergers (1856) stated that the finest specimens were in the Weisbaden Museum. Specimens from Winterberg, Germany in BM (N.H.) (fide H. W. Ball). Remarks. — This species was first listed in 1 842, but not described, as Chiton subgranosus, a name that was dropped for no apparent reason and subsequently described and illustrated as Chiton corrugatus by the Sandbergers in 1856. De Ko- ninck and Baily considered C. corrugatus, C cordiformis Sandberger, 1845, C priscus Sand- berger, 1842 (non Minister, 1839), and C. sand- bergianus de Ryckholt, 1845 to be conspecific and grouped them under a single number in their species lists. Rochebrune treated C subgranosus Sandberger, 1842, C priscus Sandberger, 1842, and C. sandbergianus de Ryckholt, 1845 as syn- onyms of C. corrugatus. Clarke included C sym- metrica Trenkner, 1868 and C trapezoidalis Trenkner, 1868 as additional synonyms. In making Chiton corrugatus the type species of Probolaeum Carpenter in Dall, 1882, Dall based it on the single specimen illustrated by the Sandbergers (1856) in their plate 26, figure 22a. Dall said that the Sandbergers' other specimens were not chitons. He also said that "among Re- cent forms this species comes nearest to Ka- tharina tunicata, but the difference is still ex- tremely great." Thus, Probolaeum corrugatum, based on a sin- gle fossil valve, rests on rather slim evidence for its validity. There seems no other course to fol- low than to retain Dall's generic assignment pending further study of Devonian polyplacoph- orans from Vilmar, Germany. coxi, Hoare and Smith, 1984, Stegochiton Stegochiton coxi Hoare and Smith, 1984:99, fig. 10A-I [type species of Stegochiton Hoare and Smith, 1984, by original designation]. Geological Age. — Lower Permian (Wolfcampian). Localities.— USA: Texas, Skinner Ranch Formation, USNM loc. 720g; Bone Spring Formation, USNM loc. 725d, Glass Mts., West Texas. Location of Material. — Holotype, USNM-330887; para- types, USNM-330892, 330893. Remarks.— Head and tail valves unknown. The species is based upon two intermediate valves which are highly arched (jugal angle averaging 95°) and vaulted. The jugal area projects ante- riorly as a false beak. The jugum is broadly rounded with central areas slightly convex and lateral areas composed of broad, raised, flat- topped ridges. The sutural laminae are large and subtriangular in shape. The surface ornamenta- tion consists of coarse, closely spaced beaded ridges draped across the lateral area and swinging diagonally across the central area. Average dimensions of the intermediate valves are: length, 7.3 mm; width, 1 1.8 mm; height, 6.0 mm. The new genus Stegochiton was erected by Hoare and Smith (1984) to include forms with the combination of broadly rounded jugum ex- tending as a false beak; vaulted, distinct lateral and central areas; broad triangular shape; and large sutural laminae. This genus may also con- tain S.I onerosus Hoare and Smith, 1984 and appears to be related to Proleptochiton Sirenko and Starobogatov, 1977. dalriensis (Etheridge, 1882), Pileochiton Chiton dalriensis Etheridge, 1882:86-89, pi. 1, fig. 1-14. Geological Age. — Lower Carboniferous (Main or Hurlet Limestone). Locality.— Scotland: Ayrshire, from the Law Quarry near Dairy (Etheridge). Location of Material. — Collections of J. Bennie, J. Arm- strong, J. Smith, and others (fide Etheridge). Present locations unknown. Remarks.— This species is based, apparently, on a fair-sized series of specimens in which in- termediate, head, and tail valves are represented. They are described and discussed in considerable detail, and are unusually well illustrated. The configuration of the valves, the granulate sculp- ture, and the well-developed sutural laminae all argue for placing the species in the genus Pileo- chiton DeBrock, Hoare, and Mapes, 1984. Ac- cording to Etheridge, there is a close analogy be- tween Chiton dalriensis and the Permian C. loftusianus King, 1850, but it differs from the latter in several important particulars in addition to being smaller in size. decorus Hoare and Mapes, 1985a, Colapterochiton Colapterochiton decorus Hoare and Mapes, 1985a:878, fig. 2. Geological Age. — Lower Pennsylvanian (Morrowan). Locality. — USA: Oklahoma, Gene Autry Formation ex- posed in gullies on east side of unnamed tributary of Sycamore SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 25 Creek on the Daube Ranch, NW'A NW'A SW'/i, sec. 2, T 4S, R 4E, Johnson Co. Rochelle 7'/2-minute Quadrangle. Location of Material. — Holotype, OSU-36992; para- types, OSU-36993-36998; BGSU-4447. Remarks. — Reconstructed specimens are me- dium-sized, about 55 mm long and ornamented with coarse granules and growth lamellae. The sutural laminae are narrow and bluntly pointed. The intermediate valves are swept forward with a large jugal sinus. The subpentagonal tail valve has a mucro posterior to midlength and arched posterior margin. Hoare and Mapes (1985a) mis- takenly stated reconstructed length as 5.5 mm. Dimensions are (mm): Head Intermediate Tail Length Width Height 2.6 4.0 1.8 7.1 10.4 3.5 11.0 12.0 4.3 depressus Bergenhayn, 1960, Chelodes Chelodes depressus Bergenhayn, 1960:175, fig. 15-16. Smith in Smith and Toomey 1964:15. Sirenko and Starobogatov 1977:31. Geological Age.— Lower Ordovician (Gasconade For- mation and Longview Formation). Localities.— USA: Virginia, 4.8 km NW of Middletown, Longview Formation, 1,000 feet below the Ceratopea zone (USGS locality 2464-Co); Missouri, 16.9 km SW of St. Clair, Franklin County (USGS locality 438-t), Gasconade Forma- tion, 4 km above the mouth of Little Indian Creek on the Merrimac River (type locality). Location of Material. — Holotype, USNM-137376. Ad- ditional specimens in USNM. Remarks. — This species is based on one weathered intermediate valve and a well- preserved tail valve from the type locality in Mis- souri, and three intermediate valves from Vir- ginia. The assignment to the genus Chelodes seems proper. depressus Bergenhayn, 1960, Preacanthochiton Preacanthochiton depressus Bergenhayn, 1960:173, fig. 4-6. Geological Age.— Lower Ordovician (Gasconade For- mation). Locality. — USA: Missouri, Hahatonka Springs, 2 km N of Decaturville, Camden County (Gasconade Formation); on top of hill on the Ellington Road, 4 km S of Centerville, Reynolds County (Gasconade Formation). Location of Material. — Holotype, USNM- 137372. Ad- ditional specimens in USNM. Remarks.— The basis for this species is an in- termediate valve (the holotype), an impression of the dorsal side of the same valve, and a tail valve. Measurements of these are not given but Bergenhayn estimated a total length, excluding the girdle, of about 28 mm, and a length to width ratio of 8. This would be a relatively elongate polyplacophoran of small size. A brief examination of these fossils by Smith led to the suspicion that they may not be poly- placophorans. More and better material is need- ed to determine the exact status of the species. The comments found under Preacanthochiton cooperi Bergenhayn, 1960 apply as well to P. depressus. discomptus, DeBrock, Hoare, and Mapes, 1984, Pedanochiton Pedanochiton discomptus DeBrock, Hoare, and Mapes, 1984: 1 123, fig. 2C, D, 4A-Z, AA, BB [type species of Pedano- chiton DeBrock, Hoare, and Mapes, 1984, by original des- ignation]. Geological Age. — Middle Pennsylvanian (Desmoinesian). Locality. — USA: Texas, Lazy Bend Formation exposed on a small tributary to Kickapoo Creek, 30 m N of where Farm to Market Road 1 189 crosses Rocky Branch, approx. 8.5 km NE of Lipan and 0.75 km S of Kickapoo Falls, Hood Co., Texas. Dennis 7'/2-minute Quadrangle. Location of Material. — Holotype, OSU-35974; para- types, OSU-35975-35992, 36195-36196 and BGSU-4224. Remarks.— A reconstructed specimen is about 23 mm long and 9 mm wide. The head valves are twice as wide as long with straight to invag- inated posterior margin and slopes straight to gently concave. The intermediate valves are nearly three times wider than long, high-arched (jugal angle averages 124°), slightly mucronate, with squared lateral margins, and short and broad sutural laminae extending to the anterolateral corner. The tail valves have broadly rounded posterior and lateral margins with a sharp an- terolateral corner, a mucro located just anterior to midlength, usually concave side and posterior slopes ending in flattened margins, and short and broad sutural laminae. The valve surfaces are ornamented with fine granules arranged in a quincunx pattern. Average dimensions are (mm): Head Intermediate Tail Length Width Height 3.0 6.9 3.2 2.2 6.9 2.3 2.8 5.2 1.4 The new genus Pedanochiton was erected to include taxa with exceptionally short, subrectan- 26 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 gular intermediate valves with short and broad sutural laminae extending to the anterolateral corners and semicircular tail valves. distortus Kirkby, 1859. Genus Incertae sedis Chitonellus distortus Kirkby, 1859:623-624, fig. 28-30. Baily 1860:95. Kirkby 1860:260-262, pi. 13, fig. 28-30. Geinitz 1861:56. Dall 1 882:283. Rochebrune 1883:41. Branson 1948: 761. Yochelson 1971:131. Chiton distortus (Kirkby). Baily 1859:333. Geological Age.— Permian. Locality. — England: Tunstall and Humbleton Hills, Dur- ham (Kirkby); Settle, Yorkshire (Rochebrune). Location of Material.— Unknown. Remarks. — Kirkby based his species on three specimens only, which are quite small in size. His three illustrations show fossils quite unpoly- placophoran in character, particularly with re- spect to the configuration of the insertion plates and especially of the sutural laminae, which are definitely not like any species in the Neoloricata, even allowing for considerable distortion during fossilization. Dall (1882:283) listed it, with oth- ers, that "have been found not to be chitons or chitonoid." Rochebrune listed it as a "sp. incer- tae." Both Geinitz and Branson stated it was not a polyplacophoran. On the basis of the above evidence, pending further study of the type material, Chiton dis- tortus Kirkby, 1859, should be dropped from the polyplacophoran fauna of the Paleozoic. eburonicus (de Ryckholt, 1845), Pterochiton Chiton eburonicus de Ryckholt, 1845:53, p. 62, pi. 4, fig. 7-8 (mislabeled as "Chiton sluseanus"). Bronn 1848:292. de Koninck 1857:195. Baily 1859:333; 1860:95. Kirkby 1862: 237. Helminthochiton eburonicus (de Ryckholt). Salter 1847:50, 52, fig. 3. Anthracochiton eburonicus (de Ryckholt). Rochebrune 1883: 29. Rhombichiton eburonicus (de Ryckholt). de Koninck 1883: 207. Pterochiton eburonicus (de Ryckholt). Dall 1882:281 [type species of Pterochiton Carpenter in Dall, 1882, by original designation]. Tryon 1883:339, pi. 85, fig. 67. Smith 1960: 153-154, fig. 36,9a-b (ex de Ryckholt). Van Belle 1 975*: 1 36, pi. 2, fig. 2a-b. Sirenko and Starobogatov 1977:36. Geological Age. — Lower Carboniferous. Locality. — Belgium: Vise. From "affleurments friables du calcaire anthraxifere superieur" (de Ryckholt). Location of Material. — Unknown. Remarks.— This species is based on inter- mediate valves with strongly-developed sutural laminae compared with those of Helminthochi- ton, in all probability representing a later evo- lutionary change. Dall pointed out that de Ryck- holt's illustrations of Chiton eburonicus are incorrectly labeled "Chiton sluseanus" De Koninck, Baily, and Rochebrune all be- lieved Chiton eburonicus to be closely related to, if not conspecific with, C gemmatus de Ko- ninck, 1844 [=C subgemmatus d'Orbigny, 1850; [non] C. gemmatus de Blainville, 1825, a Recent species]. They list it first as a subspecies and later as a synonym of C. gemmatus de Koninck, 1 844. Rochebrune said he thought an unnamed spec- imen in the Paris School of Mines from Kildare, Ireland, was probably C eburonicus although he may have been referring to a specimen of C. thomondiensis Baily, 1859 from the Carbonif- erous limestone of County Limerick. According to Dall ( 1 882) the genus Pterochiton included P. eburonicus (the type sepcies); P. le- giacus (de Ryckholt, 1845); P. gemmatus (de Koninck, 1844) [at least in part], P. thomon- diensis (Baily, 1859); P. sandbergianus (de Ryck- holt, 1 845); and P. sluseanus (de Ryckholt, 1 845). elevatus (Kues, 1978), Gryphochiton Pterochiton elevatus Kues, 1978:308-309, pi. 2, fig. 3, 8. Geological Age. — Middle Mississippian (Meramecian). Locality.— USA: Indiana, abandoned Cleveland quarry, SE'A NW'A, sec. 20, T 7N, R 1 W, about 16 km south of Bloom- ington and 1.8 km north of Harrodsburg, Monroe County. Location of Material. — Holotype IU 13892 Department of Geology, Indiana University, Bloomington and paratype USNM-244958. Remarks.— Head and intermediate valves un- known. Tail valve wider than long, highly arched with steep side slopes. Blunt mucro located in posterior fifth of length with steep rugose pos- terior slope below it. Posterior margin arched upward. Sutural laminae short, narrow and hemielliptical. Central area triangular, widening from mucro to form entire anterior margin, and bounded by shallow furrows. Holotype is 4.7 mm long, 5.5 mm wide, and 3.2 mm high. A paratype is 6.9 mm long, 7.5 mm wide, and 5.1 mm high. The posterior position of the mucro, arched posterior margin, shape and size of the sutural laminae, and the highly arched nature of the tail valve seem to be consistent with the general char- acteristics of the genus Gryphochiton Gray, 1 847a rather than Pterochiton Carpenter in Dall, 1882. The lack of information concerning the inter- SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 27 mediate valves and the ventral surface of the tail valves leaves a question as to the correct place- ment. The amount of variability in the location of the mucro, development of heavy growth ridges, and degree of arching of the tail valve in G. parvus (Stevens, 1858) is unknown. Gry- phochiton elevatus, which is associated with G. parvus may possibly be a variant of the latter species. elongata (Hadding, 1913), Solenocarisl Anatifopsisl elongatus Hadding, 1913:67, pi. 4, fig. 34. Had- ding 1915:31, pi. 4, fig. 27. Giirich 1929:49. Rolfe 1981: 675. Geological Age. — Upper Ordovician (Llandeilo-Cara- doc). Locality.— Sweden: Collected from exposures along the Laesaa and Riseback rivers, southwest of Aakirkeby. Location of Material.— Type material in repository of Department of Historical Geology and Paleontology, Lund University, Sweden. Remarks. — Hadding was uncertain as to the biological affinity of this species believing it might be a phyllocarid crustacean. Giirich (1929) com- pared it to Solenocaris. Since the tail valve is incomplete this assignment must remain provi- sional. elongatus Wx, 1984, Yangtzechiton Yangtzechiton elongatus Yii, 1984:24-25, pi. 1, fig. 1-7. Geological Age. — Lower Cambrian (Meishucun). Locality. — China: Zhongyicun Member, Dengying For- mation in eastern Yunnan Province and Huangshandong Member, Tongying Formation in the Yichang District, western Hubei Province. Location of Material. — Holotype 84131, paratype 84132, Nanjing Institute of Geology and Palaeontology, Academia Sinica. Remarks.— This species is described by Yii (1984) as follows: "—characterized by the pos- session of a minute-sized shell of an elongated vermiform and complete coverage. The head valve is small, with a rounded anterior margin, and the posterior margin bears a broadly deep sinus. The intermediate valves are longer than wide with one-half of the valve overlapped by the preceding ones. On the dorsal side at least five valves can be seen clearly, with an elevated elliptical hole in the anterior part of the inter- mediate valves, which may be the remains of the empty spine after falling off. On the ventral side, all the valves are contiguous with each other and are combined into a single body, but the contig- uous fissures still can be seen clearly. In the head valve there is a reniform concavity in the anterior margin and a concave median furrow in the pos- terior (PI. I, fig. 3). Of special interest is the oc- currence of a varied kind of spicules on the dorsal and ventral sides of the intermediate valves, which may be either separately scattered or gath- ered in bunches." The silicified material illustrated by Yii ( 1 984) is composed of incomplete articulated specimens with the holotype, consisting of the head and two intermediate valves being 0.96 mm long and 0.42 mm wide, and a paratype, consisting of the head and four intermediate valves being 0.54 mm long and 0.18 mm wide. The elevated hole on the intermediate valves may well represent an orig- inal spinose structure. The degree of overlap of the valves and preservation of spicules are un- usual. No evidence of sutural laminae or inser- tion plates present. A new family, Yangtzechi- tonidae, erected by Yii, includes Yangtzechiton and Luyanhaochiton, the latter having spinose projections on the intermediate valves. etheridgei n. sp., Acutichiton Chiton cordatus Kirkby. Etheridge 1882:93-94, pi. 1, fig. 20- 22. Geological Age. — Lower Carboniferous. Locality. — England: From the Main or Hurlet Limestone, Law Quarry, near Dairy, Ayrshire (Etheridge). Location of Material.— Collections of J. Bennie, J. Smith, etc. (fide Etheridge). Present location of material unknown. Remarks.— The specimens described by Eth- eridge as Chiton cordatus Kirkby, 1859 are rad- ically different from those described by Kirkby particularly in the presence of a well-developed hypotyche on the tail valve. Etheridge says "Viewed from the interior the plate is seen to be of considerable thickness towards the posterior, forming a smooth triangular surface of attach- ment destitute of markings of any kind." This feature plus the terminal mucro, triangular shape, and narrow, but well-developed sutural laminae differentiates this species from Chiton cordatus Kirkby, 1859. These characteristics also allow the species to be placed in Acutichiton Hoare, Sturgeon, and Hoare, 1972. The specimen illustrated by Etheridge on plate 1, figures 20 and 21 is hereby selected as the lectoholotype for the species. 28 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 Using Etheridge's illustrations and stated mag- nifications the lectoholotype is about 3.2 mm long, 2.8 mm wide, and 1.2 mm high. The length of the hypotyche along the median line of the second specimen is 0.88 mm. exsectionis Trenkner, 1868, "Chiton" Chiton exsectionis Trenkner, 1868:137, pi. 2, fig. 31. Clarke 1885:340, pi. 4, fig. 18-19. Geological Age. — Upper Devonian. Locality. — Germany: Ohemannsbrink, Hartz Mts. Location of Material. — Unknown. Remarks.— Based on a single tail valve, a steinkern, close to Chiton inflatus Trenkner, 1868. Measurements are: length, 16 mm; width, 13 mm. expansa, Ulrich and Bridge in Butts, 1941, Hemithecella Hemithecella expansa Ulrich and Bridge in Butts, 1941:1 9-20, pi. 68, fig. 6 [type species of Helmithecella Ulrich and Bridge, 1941]. Runnegar, Pojeta, Taylor, and Collins 1979:1389, pi. 1, fig. 31,32. Geological Age. — Lower Ordovician (Gascondian). Locality. — USA: Missouri. Gasconde Dolomite, USNM loc. 104 (old series), Decaturville, Camden County. Location of Material. — Holotype, USNM-96211; para- type (?) USNM-97289. Remarks.— The holotype is a silicified exter- nal mold of a body valve. The mold of the filling of the posterior hole and the growing edge of the valve is preserved. Runnegar et al. (1979) said that the preservation of the questionable para- type figured by Ulrich and Bridge in Butts (1941) is not well enough preserved to definitely assign it to this taxon. They also said that Hemithecella expansa is intermediate in form between Mat- thevia and Chelodes. fasciatus Sandberger, 1 842 Chiton fasciatus Sandberger, 1842:399. Nomen nudum, de Ryckholt 1845:62. Salter 1847:49, 51 (footnote). Bronn 1848: 292. de Koninck 1857:192 (and footnote). Baily 1859:333; 1860:92 (and footnote). Rochebrune 1883:22-23. See: Chiton sagittalis Sandberger and Sandberger, 1856 which replaces this species name. Remarks. — Chiton fasciatus was introduced but not described by Guido Sandberger in 1842. In any event, the name fasciatus was nomencla- torially unavailable in 1842, being preoccupied by Chiton fasciatus Wood, 1815 [=C. squamosus Linne, 1 764], by Chiton fasciatus Quoy and Gai- mard, 1835 [=Cryptoplax larvaeformis (Burrow, 1815)], and possibly also by Chitonellus fascia- tus, Reeve, 1847 [=Cryptoplax oculatus Quoy and Gaimard, 1835]. fornicis, Hoare and Smith, 1984, Lekiskochiton Lekiskochiton fornicis Hoare and Smith, 1984:95-96, fig. 70- X [type species of Lekiskochiton Hoare and Smith, 1984, by original designation]. Geological Age. — Middle Permian (Leonardian). Localities.— USA: Texas, Road Canyon Formation, USNM loc. 726d, 726z, Glass Mts., West Texas. Location of Material. — Holotype, USNM-330863; para- types, USNM-330864, 330873. Remarks.— Known only from three speci- mens, one intermediate and two tail valves, Le- kiskochiton fornicis appears to be closely related to some of the specimens described as Chiton cordatus by Kirkby (1859), especially those in- dicated as intermediate valves (pi. 16, fig. 25, 26), from the Permian of the British Isles. His illustrations of tail valves are discounted as poly- placophoran remains. Based upon an illustration by Kirkby and Young (1867) the head valve of this genus may be narrowly triangular with a prominent apex, although none have been recovered from the Permian of West Texas. The intermediate valve of Lekiskochiton fornicis is cordate in shape, low- arched (jugal angle averages 135°), with a raised jugal area, a small apical area, and narrow sutural laminae although the anterior extensions of the laminae are missing. The tail valve is narrowly triangular in shape with an overhanging, termi- nal mucro above an arched posterior margin, and narrow sutural laminae. The valves are smooth except for coarse, irregular ridges on the lower side-slopes which intersect the lateral margins. Average dimensions are (mm): Intermediate Tail Length Width Height 8.5 6.8 2.4 6.7 4.1 3.1 The new genus Lekiskochiton Hoare and Smith, 1984 was erected to include those species with cordate or subtriangular intermediate and tail valves that are low-arched and have an elevated terminal mucro above an arched posterior mar- gin. SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 29 geikiei (Etheridge, 1882), Chauliochitonl Chiton geikiei Etheridge, 1882:94-95, pi. 2, fig. 1-3. Geological Age. — Lower Carboniferous (Main or Hurlet Limestone). Locality.— Scotland: Ayrshire, from the Law Quarry near Dairy (Etheridge). Location of Material.— Collection of J. Smith (fide Eth- eridge). Present location of material unknown. Remarks.— This species is well described by Etheridge, based on both head and tail valves, the latter with small but rather broad sutural laminae. The head valve is "semi-conical, snout- like, and convex, anteriorly pointed, posteriorly truncately rounded." Ventrally, it has an exten- sive apical area. The tail valve is described as rectangular with a broadly-rounded, posterior margin, but it appears that the illustration is of an articulated semicircular tail valve and subquadrate intermediate valve. Major sculpture on the head valve consists of blunt, microscopic tubercles arranged in transverse lines, on the tail valve, fine granulations. The lateral margins of the head valve and the posterior margin of the intermediate valve are decorated with a row of projections, or pectinations (Etheridge called them acute spinelets), a sculptural feature not hitherto reported to occur on any Paleozoic species, but reminiscent of a somewhat similar sculptural characteristic of Recent species in the genus Lepidozona in the Ischnochitonidae. Hoare and Smith ( 1 984:96) have described a new genus, Chauliochiton, from the Permian of West Texas which has spines along the posterior margins of the intermediate valves. Head and tail valves are unknown. Assignment of Chiton geikiei to this genus is provisional. Valve measurements were not supplied by Etheridge (1882). These would be about as fol- lows, based on the scale of his illustrations (mm): Valve Length Width Head Intermediate Tail 1.9 1.5 1.0 + 2.6 2.3 2.0 The present systematic position of Chiton gei- kiei is problematical and its assignment to Chau- liochiton at this time may be premature, the shape of the intermediate valves and ornamentation being radically different. Chiton gemmatus de Koninck, 1844:323, pi. 23, fig. 2a-e. See: subgemmatus d'Orbigny (1850). Remarks. — De Koninck's name is preoccu- pied by Chiton gemmatus de Blainville (1825), a Recent species. Renamed by d'Orbigny in 1850. gibberosus (Sardeson, 1896), Chelodes Ascoceras gibberosum Sardeson, 1896:102, pi. 6, fig. 8-10. Chelodes gibberosus (Sardeson). Smith in Smith and Toomey 1964:14. Geological Age. — Lower Ordovician (Oneonta Dolomite). Locality. — USA: Minnesota, Dresbach, in the Oneonta Dolomite. Location of Material.— Type and related specimens in the Department of Geology, University of Minnesota. Pho- tographs in CAS. Remarks. — Examination of the type and other valves of this species established the fact that it should be assigned to the Paleoloricata, genus Chelodes. The holotype is a well-preserved in- termediate valve. There are two other quite sim- ilar valves. These measure (mm): Max. thickness Valve Length Width Height at jugum Holotype 15.0 8.5 7.9 * Valve A 13.0 8.1 6.8 4.0 Valve B 13.0 9.6 * 4.3 * These dimensions could not be taken accurately. All three valves are much alike, with the an- terior end notched by an almost semicircular si- nus, and the posterior end rounded. They differ in shape from Chelodes bergmani Davidson and King, 1874, which has a nearly squared-off an- terior and a much more pointed posterior mar- gin. In Valve A the internal ridge is broadly V-shaped, the distance from the valve margins to the posterior margin being 6.6 mm, while from the center of the ridge along a median line this distance is 4.8 mm. There is another valve in the series, which may be a head valve. This has a sharply pointed pos- terior end, with the tegmentum rolled over onto the ventral side, forming a V-shaped pocket un- der the valve apex. The anterior margin is not complete but gives the impression of having a shallower anterior sinus than occurs on the other three valves. This possible head valve is 12.4 mm long and has a maximum width of 9.4 mm. gemmatus de Koninck, 1842 cf. gibberosus Sardeson, 1896, Calceochiton 30 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 Calceochiton cf. C. gibberosus (Sardeson, 1896). Flower 1968: 10, pi. 1, fig. 10-24. Geological Age.— Lower Ordovician (Oneonta Dolomite). Locality. — USA: Near Sauk City, Wisconsin. Location of Material. — Figured specimens 1269-1274, New Mexico Bureau of Mines and Mineral Resources. Remarks. — "These chiton plates from the Oneonta show some variation in proportions, illustrated in our PI. 1, fig. 10-24, but show rounded dorsal surfaces in cross section, nearly straight sides, gently converging apically, and concave anterior margins. Rate of expansion var- ies from the broad form shown in fig. 10, to the slender one in fig. 1 8; in profile some plates are convex dorsally, others straight, while fig. 17 shows a shell that is slightly concave. "This is allied to the preceding form [Calceo- chiton hachitae Flower, 1 968], but is larger, shows better growth lines, the shell shows less apical thickening, and we have no specimens in which the ventral cavity is surely enclosed below. These forms are figured here as examples of a relative of C. hachitae in the Oneonta Dolomite of Gas- conade age. Further work may show more than one species in this association and may be the explanation of the wide variation in profile and rate of expansion" (Flower 1968:10). The conservative taxonomic approach would be to identify this material as Calceochiton ha- chitae until additional data are obtained that prove otherwise. The valves from Sauk City should not be equated with Chelodes gibberosus Sardeson, 1896 which is subquadrate in shape, not lanceolate, although both series of valves are found in the Oneonta Dolomite, the latter being collected near Dresbach, Minnesota. gibbosus Trenkner, 1868, "Chiton" Chiton gibbosus Trenkner, 1868:138, pi. 2, fig. 33. Clarke 1885: 339, pi. 4, fig. 12, 13. Geological Age.— Upper Devonian. Locality.— Germany: Winterberg, Hartz Mts. Location of Material. — Unknown. Remarks.— The type is an intermediate valve measuring: length, 12 mm and width, 20 mm. It is the only specimen that has been described or illustrated. The posterior and anterior margins are subparallel with the lateral margins converg- ing anteriorly giving a trapezoidal shape. A deep furrow crosses the valve at about midline form- ing two pronounced humps along the jugal area, both of which project over the valve margins. Sutural laminae are described as strongly devel- oped and sloping. The valve surface is orna- mented by numerous, fine, closely spaced, irreg- ular, concentrically arranged ridges composed of small tubercles. girtyi (Hoare and Smith, 1984), Gryphochiton Helminthochiton girtyi Hoare and Smith, 1984:92-93, fig. 6 (reconstruction), 7A-G. Geological Age. — Middle Permian (Leonardian). Locality. — USA: Texas, Road Canyon Formation, USNM loc. 726d, Glass Mts., West Texas. Location of Material. — Holotype, USNM-330865; para- types, USNM-330866-330872. Remarks.— A reconstructed specimen mea- sures approximately 65 mm in length and 1 5 mm in width, giving a length to width ratio of 4.3:1. The head valve is unknown. The intermediate valves are subquadrangular, low-arched Ougal angle averages 1 1 5°), with straight side-slopes only slightly set off from jugal area, and probably small and narrow sutural laminae although they are not well preserved. The tail valves are broadly subtriangular to subquadrate in plan view, low- arched, with distinct jugal area, and mucro lo- cated close to posterior margin. Sutural laminae not preserved. Ornamentation of heavy growth lamellae paralleling the anterior and lateral mar- gins on the intermediate valves and similar la- mellae on the lateral and posterior margins of the tail valves. The fine granular ornamentation, normally present on specimens of Gryphochiton appears not to have been preserved in the sili- ceous replacement of these specimens. Average dimensions are (mm): Intermediate Tail Length Width Height 10.3 11.3 4.1 10.0 13.2 5.1 gotlandicus Lindstrom, 1884, Chelodes Chelodes gotlandicus Lindstrom, 1884:51-52, pi. 2, fig. 9-27. Etheridge 1897:69. Bergenhayn 1955:9-12, pi. 1, fig. 1-2; pi. 2, fig. 1. Sirenko and Starobogatov 1977:31. Geological Age. — Silurian (Gotlandian) [Lindstrom]. Middle Silurian (Etheridge). Localities. — Sweden: Grotlingbo (several specimens); oo- lite quarry near Gannviken; sandstone at Burgsvik; oolite near Rone; limestone above Kalens qvarn, near Visby (Lindstrom). Wenlock, Gotland (Etheridge). Location of Material. — Holotype, RM-5098 and addi- tional specimens (fide Bergenhayn, 1955). SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 31 Remarks.— The species is based on both in- termediate and tail valves. One intermediate valve is massive and has a length of 17.3 mm. The anterior margin has a deep sinus compared with Chelodes bergmani Lindstrom, 1884, which has an almost straight anterior margin, without the slightest evidence of any emargination. The apex of C gotlandicus is more rounded than in C. bergmani, which tends to be pointed. Bergen- hayn calculated a total shell length, exclusive of the girdle, of about 1 02 mm for the species. Lindstrom said that both species were found together, C bergmani being of much rarer oc- currence. grayanus de Koninck, 1857, "Chiton''' Chiton grayanus de Koninck, 1857:196-198, pi. 1, fig. la-d. Baily 1859:333. de Koninck 1860:96-97, pi. 2, fig. la-d. Woodward 1865:487. Dall 1882:283. Rochebrune 1883:19. Geological Age. — Lower Silurian (Wenlock Limestone) (de Koninck). Upper Silurian (Baily (1860), Dall, Rochebrune). Locality. — England: Dudley, Worcester (north of Birming- ham). Location of Material. -BM (N.H.) (fide H. W. Ball). Remarks.— The original description of Chiton grayanus is based on intermediate valves only, no end valves having been found. Insertion plates, if any, are not preserved. De Koninck gave the length of a valve as about 1 2 mm and the width about 10 mm. He estimated a complete animal would have been 80-90 mm long and 16-18 mm wide. De Koninck's drawings are stylized. His figure la is of a piece of matrix with fragments of four valves, two of which are adjacent, apparently in normal position. Figure lb shows an end view of a complete valve. Figure lc is an enlarged view of sculptural detail. Figure Id is a hypothetical reconstruction of the valves of an entire animal, the configuration of the end valves being pure guesswork. From the description and figures the intermediate valves are almost square, the an- terior corners rounded, and the anterior margins slightly emarginate; the side margins are straight. Dall (1882) said Chiton grayanus was not a polyplacophoran, listing it with others he thought were fish scales, barnacle plates (Turrilepas), os- tracode crustaceans, or other undetermined or- ganisms. Because of the uncertainty of the ex- istence of sutural laminae or insertion plates (or both), this species cannot be assigned to any pres- ently recognized families or genera with confi- dence. If, on subsequent study, the valves lack an articulamentum layer this species could be assigned most probably to the family Gotlan- dochitonidae; if such a layer is present this species could be placed in the Lepidopleuridae. De Ko- ninck compared his species with Gryphochiton priscus (Minister, 1839) and G. mempiscus (de Ryckholt, 1 845), both Carboniferous species in the Lepidopleuridae. grayi de Ryckholt, 1862. Genus incertae sedis Sulcochiton grayi de Ryckholt, 1862:259-260, pi. 12, fig. 14. Dall 1879:315. Etheridge 1882:86. Dall 1882:283. Roche- brune 1883:35-36. Tryon 1883:339. Fischer 1885:879. Ire- dale and Hull 1926:326; 1927:141. Geological Age. — Lower Carboniferous. Locality. — Belgium: Vise. Location of Material. — Unknown. Remarks.— This species was considered by Dall, Etheridge, and other reviewers as not being a polyplacophoran, a view that seems to be cor- rect. It is based on a small head(?) valve, divided into two halves by a half-obliterated groove pass- ing from the summit to the margin. From the illustrations it appears more likely to be a species of brachiopod. grayiae (Woodward, 1885), Septemchiton Helminthochiton grayiae. Woodward, 1885:352, pi. 9, fig. 7- 10 [non Reed, 1907:1 13-1 14, pi. 4, fig. 8 (mislabeled as fig. 12)]. Robson 1913:304. Septemchiton vermiformis Bergenhayn, 1955:24-26, pi. 1, fig. 15 (type), pi. 2, fig. 13 (reconstruction), 13a-b. Smith 1960: 150, fig. 35,la-f (ex Bergenhayn). Van Belle 1975a: 126, pi. 1, fig. 11. Sirenko and Starobogatov 1977:32, fig. lc, d, 2c. Septemchiton grayiae (Woodward). Rolfe 1981:677, text-fig. 1, 2 [type species of Septemchiton Bergenhayn, 1955]. Geological Age. — Upper Ordovician (Ashgillian). Locality. —Scotland: Upper Bala beds at Thraive, near Gir- van, Ayrshire (Woodward). Starfish bed, Drummock Group, Ashgill, Lady Burn, Girvan (Robson, Rolfe). Location of Material. — Woodward's figured specimen (holotype?) and Reed's figured specimen (hypotype?) along with other related material in BM (N.H.) (fide H. W. Ball). Addi- tional material figured by Rolfe ( 1 98 1 ) in the Begg and Lamont collections at the Hunterian Museum, Glasgow University (HM S. 3828/1 and HM S. 14902a). Remarks. — Bergenhayn's (1955) interpreta- tion of this form as a 7-valved species has been shown to be incorrect by Rolfe (1981). The type and additional material shows a small head valve present. The erection of a separate suborder, Sep- temchitonina by Bergenhayn is unnecessary. Septemchiton vermiformis Bergenhayn (1955) is 32 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 a subjective junior synonym of S. grayiae (Woodward, 1885). Both Reed (1907) and Rob- son (1913) doubted this species is a polyplacoph- oran, believing it may be a crustacean. Rolfe's diagnosis appears correct. Rolfe in Morris (1967) had synonomized Septemchiton with Solenocar- is Young and Young in Young, 1868. griffithi Salter in McCoy, 1 846, Helminthochiton Helminthochiton griffithi Salter in McCoy, 1846, addenda:71, pi. 5, fig. 5a-e [type species of Helminthochiton Salter, 1846, by original designation]. Salter 1847:51, fig. 6. Etheridge 1882:85. Dall 1882:280. Rochebrune 1883:18-19, pi. 3, fig. 7. Tryon 1 883:339, pi. 85, fig. 58. Smith 1960:152, fig. 36,2a- b. Sirenko and Starobogatov 1977:33. Chiton {Helminthochiton) griffithi (Salter), de Koninck 1857: 193, 196. Baily 1859:333; 1860:96. Geological Age. — Silurian (Salter). Lower Silurian (Roche- brune). Locality. — Ireland: Cong, County Galway. Location of Material. — Unknown. Remarks.— This is the type species of Hel- minthochiton Salter in McCoy (1846), by origi- nal designation. Salter ( 1 847) says: "Mr. Griffiths found it a year or two back in the silty mudstone overlying the fossiliferous conglomerate of Cong, co. Galway." Sirenko and Starobogatov (1977) disagree with the assignment of Helminthochiton griffithi to the Loricata and place it in the Paleoloricata. Because of the uncertainty of the characteristics of this taxon the upper Paleozoic species, which have commonly been assigned to Helmintho- chiton, are here assigned to Grvphochiton Gray, 1847a. hachitae Rower, 1968, Calceochiton Calceochiton hachitae Flower, 1968:10, pi. 1, fig. 1-9 [type species of Calceochiton Flower, 1968, by original designa- tion]. Van Belle 1975a: 124, pi. 1, fig. 4a-c. Sirenko and Starobogatov 1977:31. Geological Age. — Lower Ordovician (Big Hatchet For- mation). Locality. — Mescal Canyon section, Big Hatchet Mts., New Mexico, in the Kainella zone in a bed 52.4 m above the base of the Paleozoic. Location of Material. — Syntypes, 1264-1266 and addi- tional unfigured specimens 1267, 1268 in New Mexico Bureau of Mines and Mineral Resources. Remarks.— "Plates of this form are without observed growth lines. The tip, generally want- ing, has the shell growing over the under side enclosing a small cavity below, and is, from in- dications of the various specimens, quite strongly pointed. The various shells show considerable variation in convexity and the nature of the cross section. PI. 1, fig. 1-3 show a strongly convex specimen, the interior of which shows a median longitudinal concave angle. The most gently rounded form is shown in PI. 1, fig. 7-9. The anterior margins of the plates, rarely perfect, are slightly concave. "These plates show some variation in propor- tion, but our greatest length is 1 1 mm, the great- est width 6 mm. They are smooth externally, thicken apically and close around the under sur- face, and are concave anteriorly" (Flower 1968: 10). Flower compared this species with valves from the Oneonta Dolomite of Sauk City, Wisconsin, which he identified incorrectly, as Calceochiton cf. C. gibberosus Sardeson, 1896. Both the Big Hatchet and the Sauk City specimens are lan- ceolate in general shape rather than subquadri- lateral with straight side-slopes, which can be assumed to be the major difference between the genera Calceochiton and Chelodes. Calceochiton Flower, 1968, undoubtedly should be allocated under the family Mattheviidae, in the order Pa- leoloricata. hami Smith in Smith and Toomey, 1 964, Gotlandochiton Gotlandochiton hami Smith in Smith and Toomey, 1964:28- 30, pi. 7, fig. 1-15. Geological Age. — Lower Ordovician (Kindblade Forma- tion). Localities. — USA: Oklahoma. Type lot from the lower part of the Kindblade Formation, Mill Creek section, Arbuckle Mts. Also from Highway 77 section interval within the Kindblade Formation, in a zone of abundant Calathium. Location of Material. — Holotype, OU-5223; paratypes OU-5224-5227, 5232. Paratypes, USNM-144541-144545. Paratypes, CAS-12593-12598. Six additional valves from the Highway 77 section are at OU. Remarks.— Valves representing this species were acid-etched from limestone blocks. No end valves were recovered. The preservation is rel- atively poor. The type lot consists of 1 7 valves, with 6 additional valves from the second locality indicated above. Distinguishing features include a fairly sharp jugal ridge, a pointed but not pro- jecting apex, a triangular jugal area that is not distinct, straight side-slopes with a slight nar- rowing of the valves anteriorly, and a well- developed apical area ranging in width from 0.5 SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 33 to 1 .0 mm. Any evidence of dorsal sculpture has been obliterated during fossilization. The holo- type valve is 8.6 mm long, 12.4 mm wide, and 5.3 mm high; thickness at the jugum is 1.5 mm; the angle of divergence is 104°. hancockianus Kirkby, 1859. Genus incertae sedis Chitonellus hancockianus Kirkby, 1859:61 1, 621-623, pi. 16, fig. 1-13. Baily 1860:95. Kirkby 1860:257-260, pi. 13, fig. 1-13. Young 1878:324. Dall 1882:283. Rochebrune 1883: 38-39. Yochelson 1971:131. Chiton hancockianus (Kirkby). Baily 1859:333. Geological Age. — Permian. Locality. — England: Durham, Tunstall, and Humbleton Hills. Location of Material. — Unknown. Remarks.— The species is based on a single, so-called tail valve, five intermediate valves, and a few fragments interpreted as girdle spines. One of Kirkby's illustrations shows a supposed tail valve, square in shape, with small, obliquely placed sutural laminae and a denticulated pos- terior margin. Dorsal sculpture consists of broad ribs radiating from a central apex. The size would be around 4.5 mm in both length and width. Other illustrations show smaller intermediate valves that are asymmetric in shape with one sutural lamina much longer than the other. The so-called spines, which are somewhat less than 2.5 mm long, have two terminal projections, like tiny sutural laminae. Both Dall and Rochebrune considered Chi- tonellus hancockianus to be a doubtful polypla- cophoran. If Kirkby's illustrations are correctly drawn, these fossils are certainly not polypla- cophoran, even allowing for considerable dis- tortion during fossilization. As for the spines, no such girdle decoration is known for any Recent species of polyplacophoran and it seems doubtful that any relationship exists between these and the so-called valves. Pending further study this species should be dropped from the list of valid Paleozoic polyplacophorans. howseanus (Kirkby, 1857), Cymatochitonl Chiton howseanus Kirkby, 1857:216, pi. 7, fig. 9-13. Howse 1858:435,463^164. Kirkby 1858:290, pi. 12, fig. 9-13; 1859: 615-616, pi. 16, fig. 42-53; 1860:248-250, pi. 13, fig. 42- 53. de Koninck 1857:198. Baily 1859:333; 1860:94. Yoch- elson 1971:131. ICymatochiton howseanus (Kirkby). Dall 1882:282. Protalochiton howseanus (Kirkby). Rochebrune 1883:37. Geological Age. — Permian. Locality. — England: Durham, Tunstall, and Humbleton Hills (Kirkby). Location of Material.— Specimens under this name in BM (N.H.) (fide H. W. Ball). Location of type material un- known. Remarks. — According to Kirkby (1857), this species is rare. In addition to the original ma- terial, he mentioned collecting four additional valves, three intermediate and one tail valve. Although some of his illustrations do not show sutural laminae, his figures 5 1-53 do show them. His original illustrations are worthless for diag- nostic purposes, but his later ones (1859) are better. In the later paper he speaks of "processes of insertion angulate, obliquely truncate, the up- per edge projecting." He thought Chiton how- seanus and C loftusianus were closely related and said that "C. priscus of the Carboniferous rocks of Belgium seem to belong to the same elongate type . . . ." Chiton howseanus has a gran- ular sculpture on the dorsal valve surfaces. In all probability, Chiton howseanus may be accepted as a valid polyplacophoran species, fol- lowing Dall (1882). Rochebrune's (1883) assign- ment to his genus Protalochiton is unnecessary. humilis Kirkby in Young, 1865, "Chiton" Chiton humilis Kirkby in Young, 1865:14, pi. 1, fig. 1. Kirkby and Young 1867:341, pi. 16, fig. 6a-c. Etheridge 1882:90. Rochebrune 1883:33. Geological Age.— Carboniferous. Locality.— Western Scotland: Calcerous shale, Robroyston beds northeast of Glasgow. Location of Material. — Unknown. Remarks. — Kirkby and Young (1867) said the species was based on an imperfect tail valve that may be a polyplacophoran. Etheridge (1882) stated his Chiton armstrongianus had an outline approaching C. humilis but was more pointed behind and less acute in front, the impressed concentric grooves were less in number and ex- hibited certain differences in shape. Another valve from Williamwood, near Cathcart, Renfrew- shire, he believed to be an intermediate form. However, Rochebrune (1883) said Kirkby's specimen should be identified as Metapoma pi- leus and therefore was not a polyplacophoran. The validity of Chiton humilis would seem questionable, although from the description and the illustrations it seems to have strong polypla- cophoran aspects. 34 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 injlatus Trenkner, 1868, "Chiton" Chiton inflates Trenkner, 1868:136, pi. 2, fig. 26. Clarke 1885: 339, pi. 4, fig. 16-17. Geological Age.— Upper Devonian. Locality.— Germany: Winterberg, Hartz Mts., in the Iber- ger Kalk. Location of Material.— Unknown. Remarks.— The species is based on a single specimen, possibly representing a head valve 33 mm long and 25 mm wide. Clarke (1885) said it somewhat resembled Chiton laevigatus Roe- mer, 1855 from the same general locality. The lack of suitable material leaves the valid- ity of Chiton injlatus in doubt. insignis Jahn, 1893. Genus incertae sedis Duslia insignis Jahn, 1893:591-603, pi. 1, fig. 1-4. Pilsbry 1900:511. Pompeckj 1912:357. von Knorre 1925:497-499, fig. 1. Quenstedt 1931:555; 1932:86. Geological Age. — Lower Silurian. Locality. — Bohemia. Location of Material. — Unknown. Remarks.— Jahn (1893) described this as a species with 12 or more valves. Pilsbry (1900) believed this to be a crustacean as did Pompeckj (1912). Knorre (1925) reinterpreted the speci- men as an 8-valved polyplacophoran, but his interpretation of the shape of the sutural laminae appears to be inconsistent with lower Paleozoic Polyplacophora. This taxon is here rejected as a polyplacophoran. intermedins Bergenhayn, 1960, Chelodes Chelodes intermedins Bergenhayn, 1960:174-175, fig. 1 1-14. Sirenko and Starobogatov 1977:31. Geological Age. — Lower Ordovician (Chapultepec For- mation). Locality.— USA: Virginia, from the Chapultepec Forma- tion 92.9 m below the Ceratopea zone, at the top of the path from office to tunnel. Natural Tunnel, Scott County. Location of Material. — Holotype, USNM- 137375. Remarks. — Chelodes intermedins is based on three intermediate valves and four tail valves. The intermediate valves are wedge-shape or heart-shaped, with an apical area as long or slightly longer than half their length. The holo- type has a length of 17 mm. Bergenhayn esti- mated the total length of the animal, excluding the girdle, to be 69 mm, with a ratio of length to width of about 4. Assignment to the genus Chelodes is correct for this species. interplicatus Bergenhayn, 1955, Gotlandochiton Gollandochiton interplicatus Bergenhayn, 1955:15-16, pi. 1, fig. 6; pi. 2, fig. 4 [type species of Gotlandochiton Bergenhayn, 1955, by original designation]. Smith 1960:150, fig. 34,4; 34,7 (ex Bergenhayn). Van Belle 1975a: 125. Sirenko and Starobogatov 1977:31. Geological Age.— Silurian (Gotlandian). Locality.— Sweden: Klints Othem, Gotland. Location and Material. — Holotype, RM Mo-6012. Remarks.— The species is based on an inter- mediate valve 10.5 mm long, which includes a fragment of another posterior to it. iowensis (Sanders, 1965), Septemchiton Bursata iowensis Sanders, 1962:102. Septemchiton iowensis (Sanders). Sanders 1965:94-98, fig. 1- 12. Geological Age.— Upper Ordovician (late Edenian). Locality.— "Depauperate Zone, basal Maquoketa Shale . . . one mile northeast of Graf, Iowa, on the northwest side of Highway 52, just beyond the second crossing of the Little Ma- quoketa River: SEVa NW'A SE'A SE'A Sec. 20, T 89 N, R 1 E" [Sanders, 1965]. Location of Material.— Co type material, OU-4470. Remarks. — These small polyplacophoran plates, ranging from 1.0-3.5 mm long and 0.5- 1.0 mm wide, were acid-etched from a glauco- nitic phosphatic shale and are abundant at the type locality. They were described originally by Ladd (1925) as Ceratiocaris (Limnocaris) prae- cedens, a phyllocarid crustacean. Rhoads (1962) restudied these fossils, concluding they were not crustacean but problematical animals, which he termed "tegmates," and described them under the new generic and specific names of Bursata iowensis, B. maquoketensis, B. bellevuensis, Sub- cylindrica elginensis, S. laddi, and Triangulata simplex. Rhoads's material came from Scales Mound, Illinois and Bellevue and Graf, Iowa, also in the basal Maquoketa Shale; his types and other specimens are deposited in the Department of Geology, State University of Iowa, Iowa City, Iowa. His illustrations of the various forms de- scribed are excellent enlargements. Further study led Sanders to the conclusion that these peculiar small fossils were, in fact, polyplacophoran plates referable to the genus Septemchiton established by Bergenhayn (1955) for a 7-valved polyplacophoran from the Middle Ordovician of south Scotland (S. vermiformis). Through the courtesy of Dr. Sanders and of Dr. SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 35 Ellis Yochelson of the U.S. Geological Survey, a large number of these fossils have been examined and we concur with the former's conclusion that they are polyplacophorans. There is no evidence, nor has it been suggested, that S. iowensis is nor- mally 7-valved; it could just as well be 8-valved. Sanders's allocation of specimens to head, inter- mediate, and tail valves seems correct. His il- lustrations also are excellent and should be stud- ied in conjunction with those furnished by Rhoads. Several features relating to Septemchiton iowensis are of special interest. The first is its small size, even assuming its habitat was a spe- cialized niche, or depauperate zone where as- sociated invertebrates all were dwarfed forms. Very few Recent polyplacophorans are normally so small and only a few even approach the pre- sumed total length of 22 mm and minimum width of 0.8 mm, with a length to width ratio of 32:1. Septemchiton vermiformis has a 17:1 ratio. The longest and narrowest known Recent polypla- cophoran is Stenochiton longicymba (Quoy and Gaimard, 1835), which has a length to width ratio of less than 7:1; other Stenochiton species (all from Australia) have ratios ranging from 3: 1 to 5:1. While the habitat of Recent Stenochiton is on or in the stipes of eel-grass this is believed to be a more recent adaptation and one might postulate that a polyplacophoran such as S. iowensis might have lived in a habitat of fine mud or muddy sand rather than on some hard substrate. Another feature is the apparent lack of overlap of one valve on another. Many of the valves have what appears to be a somewhat everted apex at the posterior margin, with a shallow sinus in the anterior margin. This might mean that in the living animal the valves merely abutted, or even that they were slightly separated as in some species of the Recent genus Cryptoplax in the adult stage. Such an arrangement would give the animal ex- treme flexibility in all directions, assuming it had a more or less normal form of girdle. An animal with such a degree of flexibility suggests a pos- sible closer ralationship between the Polypla- cophora and the Aplacophora than has hitherto been apparent from the fossil record (there being none for the latter subclass). Although all soleno- gastres (Aplacophora) lack any calcareous plates when adult, it has been shown that some species do form such plates in the larval stage of devel- opment and that these are adsorbed long before the animal becomes adult. The evolutionary im- plications of such a relationship if, in fact, it can be shown to exist, are of more than passing in- terest. Many of the plates of Septemchiton iowensis show a well-preserved network of rather coarse, cylindrical punctae filled with a darker phos- phatic material (Sanders 1965, fig. 3, 9; Rhoads 1962, pi. 178, fig. 9 especially). These are easily seen under magnification in many of the plates at hand. No other Paleozoic polyplacophoran valves have been seen to exhibit this feature. Sanders pointed out (1 965:95) that these punctae "lack the interconnecting canal system of the 'eyes' of modern chitons." Whether or not this is a character that is general for all primitive polyplacophorans or is limited to this particular species one cannot now say. It certainly is unique as far as present knowledge of the group extends. juxtater minus Hoare and Mapes, 1985a, Elachychiton ElachychitonjuxtaterminusHoaTeandMapes, 1985a:880-881, fig. 3. Geological Age. — Upper Mississippian (Chesterian). Locality. — USA: Arkansas, Imo Formation exposed in roadcut just south of the Van Buren Co. border on U.S. Hwy. 65, about 6.4 km SE of Leslie, NE'/t, sec. 1 1, T 13N, R 15W, Searcy Co. Leslie 7'/2-minute Quadrangle. Location of Material. — Holotype, OSU-36999; para- types, OSU-37000-37008; BGSU-4449. Remarks. — Reconstructed specimens are small, about 20 mm long with fine granulose ornamentation. The intermediate valves are highly arched with broadly rounded sutural lam- inae. The tail valve is triangularly elongate with a well-developed hypotyche and a mucro located just anterior to the posterior margin. The head valve is unknown. Average dimensions are (mm): Intermediate Tail Length Width Height 2.3 3.3 1.6 5.6 2.6 kaibabensis (Brady, 1955), Cymatochitonf Rhynchoteuthis kaibabensis Brady, 1955:102-104, pi. 21. Cymatochiton? kaibabensis (Brady). Yochelson 1971:130-133, text-fig. 1A-J. Geological Age. — Middle Permian. Locality. — USA: Arizona (Kaibab Limestone). 36 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 Location of Material. — Holotype, G2.351; paratypes, G2.6626 and G2.1672, Museum of Northern Arizona. Remarks.— The material consists of three specimens originally described by Brady (1955), who believed them to be the calcified part of cephalopod mandibles— presumably nautiloids (rhyncholites). Yochelson (1971) has interpreted them correctly as the interior impressions of iso- lated polyplacophoran valves, assigning them with some question to the genus Cymatochiton Dall, 1 882. This generic assignment seems prop- er, considering the fact that these specimens have a general resemblance to the type species of Cy- matochiton— C. loftusianus (King, 1850). Their relationship to C.I texanus Girty, 1909, is dif- ficult to determine on account of the small num- ber and the poor preservation of the valves of both species. Neither C.I texanus nor C? kai- babensis has any close relationship to the Perm- ian species that are abundant in strata at the border between the Wolfcampian and the Leo- nardian formations in the Glass Mountain and equivalent areas of West Texas. Cymatochiton? kaibabensis, however, has the same general shape as a large, intermediate, unidentified polypla- cophoran valve from the Permian of Palermo, Sicily (Socio Limestone), in the collection of the USNM (loc. no. 755, ace. no. 179820). kindbladensis Smith in Smith and Toomey, 1964, Paleochiton Paleochiton kindbladensis Smith in Smith and Toomey, 1964: 20-22, pi. 3, fig. 1-14 [type species of Paleochiton Smith, 1964, by original designation]. Van Belle 1975a: 124, pi. 1, fig. 3a-c. Sirenko and Starobogatov 1977:33. Geological Age. — Lower Ordovician (Kindblade Forma- tion). Locality. — USA: Oklahoma, from the lower part of the Kindblade Formation, Mill Creek section, Arbuckle Mts. Location of Material. — Holotype, OU-5211; paratype, OU-5212. Paratype, CAS-12586. Paratype, USNM-144583. Remarks.— In the genus Paleochiton the in- termediate valves are longer than wide, rectan- gular, with an acute jugal ridge, and straight side- slopes. The dorsal surface is not divided into clearly defined shell areas. It is assigned to the family Gotlandochitonidae, Bergenhayn, 1955. Paleochiton kindbladensis, type of the genus, is based on four intermediate valves; the head and tail valves are unknown. The holotype measures: length, 13.4 mm; width, 11.2 mm; height, 5.5 mm; width of apical area, 1.2 mm; the angle of divergence of the side-slopes is 1 1 4°. Specimens were acid-etched from limestone blocks and have been much altered during fossilization, only a few major sculptural elements being preserved. The valves were found in association with sponges of the genera Calathium and Archaeoscyphia. kirkbyanus (Etheridge, 1882), Glyptochiton Chitonellus kirkbyanus Etheridge, 1882:100-101, pi. 2, fig. 14- 22. Glyptochiton kirkbyanus (Etheridge). Smith 1971:567, 572. Geological Age. — Lower Carboniferous (Main or Hurlet Limestone). Locality. — Scotland: Ayrshire, Law Quarry near Dairy. Location of Material.— Collections of J. Bennie, J. Arm- strong, J. Smith, etc. (fide Etheridge). Present location of type or other specimens unknown. Remarks.— This is another of the species be- longing under the genus Glyptochiton de Ko- ninck, 1883 with G. cordifer (de Koninck, 1844) from the Carboniferous of Belgium as the type species. It is well described and illustrated from specimens representing both end valves, inter- mediate valves, and one presumed to be valve ii in position sequence. From the description and illustrations it appears different from G. subquadratus (Kirkby and Young, 1867), G. quadratus (Etheridge, 1882), and G. youngianus (Kirkby and Young, 1867). Etheridge pointed out that the tail valve illus- trated by de Ryckholt (1845, pi. 4, fig. 10) for Glyptochiton cordifer closely resembles the tail valve of G. kirkbyanus. kirkbyi (de Koninck, 1883), Cymatochiton? Chiton sp. Kirkby, 1862:236, fig. 9-10. Rhombichiton kirkbyi de Koninck, 1883:209-210, pi. 53, fig. 37-41. Geological Age. — Lower Carboniferous (Lower Scar) (Kirkby). Tournaisian (de Koninck). Localities.— England: Settle, Yorkshire, in the Mountain Limestone (Kirkby). Belgium: Vise (de Koninck). Location of Material.— Unknown. Remarks. — Kirkby reported an intermediate valve, found at Settle, Yorkshire, in 1 862 but did not name it at the time. It is much wider than long, and he would have identified it as Chiton loftusianus King, 1848 had it come from the Permian. It measures: length, V5 in. (5 mm); breadth, 6/10 in. (1 5 mm). The valve is rather high- arched with a mucronate apex and a distinct dor- SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 37 sal ridge. The sutural laminae are short and wide; the sutural sinus is shallow and broad. De Koninck named this valve in 1883, as- signing it to his genus Rhombichiton, and said it also occurred in the Tournaisian of Vise, Bel- gium. knighti, Hoare and Smith, 1984, Chauliochiton Chauliochiton knighti Hoare and Smith, 1984:96-97, fig. 8 (reconstruction), 9A-J [type species of Chauliochiton Hoare and Smith, 1984, by original designation]. Geological Age. — Lower and Middle Permian (Wolfcam- pian, Leonardian). Localities. — USA: Texas, Bone Spring Formation, USNM loc. 725d; Road Canyon Formation, USNM loc. 709c, 72 lj, 72 lz, 726d, Glass Mts., West Texas. Location of Material. -Holotype, USNM-330882; para- types, USNM-330883-330886. Remarks.— A reconstructed specimen is ap- proximately 50 mm in length and 15 mm in width with a length to width ratio of 3.3:1. The head and tail valves are unknown. The inter- mediate valves are highly arched Gugal angle av- eraging 97°) and strongly swept- wing in shape with a deep jugal sinus and with the apical angle averaging 79°. The jugal ridge is narrow and prominent and the side-slopes slightly convex. A distinct raised lateral area consists of two ridges with the inner ridge bearing several prominent spinose processes. The apical area is large and the sutural laminae are short and broadly round- ed, coinciding with the width of the narrow an- terior margins. The entire surface is ornamented by closely spaced, flat-topped ridges giving a clap- board appearance. Average dimensions of the intermediate valves are: length, 9.9 mm; width, 14.7 mm; height, 7.2 mm. The new genus Chauliochiton Hoare and Smith, 1 984 was erected to embrace Paleozoic taxa hav- ing spinose processes bordering valve margins. "Chiton" geikiei Etheridge, 1882 has been pro- visionally assigned to this genus. laevigatus Roemer, 1855, "Chiton"'' Bellerophon expansusl Sowerby. Roemer 1843:32, pi. 9, fig. 5. Pictet 1845:300. Chiton laevigatus Roemer, 1 855:36, pi. 7, fig. 8a-b. de Koninck 1857:196. Baily 1859:333; 1860:95. Rochebrune 1883:24. Clarke 1885:337. Chiton sp. Roemer, 1855:148, pi. 22, fig. 9. Chiton sella Trenkner, 1868:136, pi. 2, fig. 27. Geological Age. — Upper Devonian. Locality.— Germany: Grund, Hartz Mts. Location of Material. — Specimens from Winterberg, Germany, in BM (N.H.) (fide H. W. Ball). Remarks.— Clarke (1885) furnished the most complete discussion of this species, in which he includes as synonyms Chiton sp. Roemer (1855), C sella Trenkner (1868), and fossils identified as Bellerophon expansus Sowerby (1839). How- ever, he did not mention Sandberger's and de Koninck's views that the latter was a synonym of Chiton cordiformis Sandberger, 1845. Roche- brune (1883) thought C. laevigatus was possibly a Metapoma (patellid gastropod) and not a poly- placophoran. Clarke supplied the dimensions of the valves of the species as follows (mm): Valve Length Width Head Intermediate* Tail 32 14 17 25 33 20 * Type of Chiton sella Trenkner, 1 868. laterodepressus (Bergenhayn, 1945), Proleptochiton Chiton sp. Etheridge, 1882:91, pi. 1, fig. 16. Lepidopleurus laterodepressus Bergenhayn, 1945:389, text-fig. 1-4. Nicolaus 1963:203, pi. 16, fig. 2a-g; pi. 18, fig. 5. Helminthochiton aff. gemmatus Schmidt, 1951:189, pi. 1, fig. 11. Proleptochiton laterodepressus (Bergenhayn). Sirenko and Sta- robogatov 1977:36 [type species of Proleptochiton Sirenko and Starobogatov, 1977, by original designation]. Rhombichiton laterodepressus (Bergenhayn). Lang, Marek, and Pek 1982:299-302, pi. l,fig. 1-10; pi. 2, fig. 1-4. Turekand Prokop 1982:288. Geological Age. — Lower and Middle Carboniferous (Di- nantian, Visean, Namurian). Localities.— Scotland: Woodmill, Fifeshire, 91.4 m below the Hosir Limestone (Bergenhayn). Czechoslovakia: Mysle- jovice Formation near Vyskov. Germany: Culm, Rheinisches Schiefergebirge Hills (Lang, Marek, and Pek). Northeastern Spain (Schmidt). Location of Material. — Bergenhayn's figured specimens (G.23441 , G.23446) and other specimens (G.23442, G.24443) in BM (N.H.). Lang, Marek, and Pek figured specimens (SKMG 700-71 1) are in the collections of the Department of Miner- alogy and Geology, Palacky University, Olomouc. Remarks.— This is a well-marked and distinct species of Paleozoic polyplacophoran. It is based on four well-preserved valves, which represent three animals, one specimen having two adjacent valves. The valves have differentiated shell areas and the dorsal sculpture is granular, of a type 38 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 generally similar to species in the genera Hel- minthochiton and Lepidopleurus. Bergenhayn's assignment to the Neoloricata, suborder Lepidopleurina, is obviously correct; but while it also falls in the family Lepidopleu- ridae, its allocation to the genus Lepidopleurus may be questioned. The valves of "L." latero- depressus are larger and shaped differently from those of Recent species in the genera (or subgen- era) Lepidopleurus, Leptochiton, Deshayesiella, and Beanella. Moreover, the genus Lepidopleu- rus s.s. is not certainly known earlier than the Pliocene, although recorded from the Eocene of France; nor have any fossil species having any similarity to "L." laterodepressus been reported from the Mesozoic. Lacking any better evidence than now is available, it seems unreasonable to assume the occurrence of the genus in its ac- cepted modern sense as far back as the Paleozoic. Sirenko and Starobogatov (1977), recognizing the differences between Lepidopleurus laterodep- ressus and modern leptochitonids, erected the new genus Proleptochiton with Lepidopleurus la- terodepressus as the type species. They appear to be correct in distinguishing Proleptochiton from Pterochiton Carpenter in Dall, 1882 and the new genus is also distinguishable from Glaphurochi- ton Raymond, 1910. laterodepressus Bergenhayn, 1955, Gotlandochiton Gotlandochiton laterodepressus Bergenhayn, 1955:17-18, pi. 1, fig. 8; pi. 2, fig. 5. Sirenko and Starobogatov 1977:31, fig. 2b. Geological Age. — Silurian (Gotlandian). Locality. — Sweden: Grotlingbo; Gansviken. Location of Material. — Holotype, RM Mo-6020. Remarks.— This species rests on the inade- quate evidence of a single, incomplete interme- diate valve estimated to be 8.57 mm long. More specimens should be collected in order to verify its validity. Gotlandochiton laterodepressus Bergenhayn, 1 955 should not be confused with Proleptochiton laterodepressus (Bergenhayn, 1945). lebescontei Barrois, 1889, Euleptochitonl Helminthochiton lebescontei Barrois, 1889: 181, 182, pi. 15, fig. 15a-c. Geological Age. — Lower Devonian (Emsian). Locality. — France. Location of Material.— Unknown. Remarks. —A simple intermediate valve is de- scribed and illustrated by Barrois (1889). The valve is slightly wider than long, with steep side- slopes and an apical angle of 80°. The sutural laminae are short and broadly rounded. A jugal ridge projects out into the concave anterior mar- gin. The surface is ornamented with "irregularly spaced pleated growth increments," which are more prominent near the margins. The specimen is 12.0 mm long and 14.0 mm wide. The wide, broadly rounded sutural laminae prevent an assignment to Gryphochiton Gray, 1 847a or to Helminthochiton Salter in McCoy, 1846. The characteristics of the valve, as well as can be discerned from the description and illus- trations of Barrois, appear to best fit those of Euleptochiton Hoare and Mapes, 1985a. The lack of information concerning the tail valve makes this a questionable assignment. legiacus (de Ryckholt, 1845), Pterochiton Chiton legiacus de Ryckholt, 1845:52, pi. 4, fig. 5-6. Bronn 1848:292. de Koninck 1857:195. Baily 1859:333; 1860:95. Kirkby 1862:237. Helminthochiton legiacus (de Ryckholt). Salter 1847:52. Pterochiton legiacus (de Ryckholt). Dall 1 882:28 1 . Sirenko and Starobogatov 1977:36. Anthrocochiton legiacus (de Ryckholt). Rochebrune 1883:28- 29. Rhombichiton legiacus (de Ryckholt). de Koninck 1883:208- 209, pi. 51, fig. 11-14, 41-42; pi. 52, fig. 18-21. Geological Age. — Lower Carboniferous. Locality. — Belgium: Vise. Location of Material. — Unknown. Remarks.— Dall included this species in the genus Pterochiton Carpenter in Dall, 1882, the type species being P. eburonicus (de Ryckholt, 1845) from the same locality. It should be noted, however, that Dall based P. legiacus on de Ryck- holt's original illustrations contained in his plate 4, figures 5-6, and plate 23, figures c-e, but not on plate 23, figures a-b. While both de Koninck (1857) and Baily (1859) list de Ryckholt's species as a subspecies of Chi- ton gemmatus de Koninck, 1844 [=C. subgem- matus d'Orbigny, 1850], they considered it to be conspecific with C. gemmatus at that time, al- though later de Koninck (1 883) included it under his genus Rhombichiton. loftusianus (King, 1850), Cymatochiton Chiton sp. King, 1844:382. King 1846:10. Howse 1848:242. SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 39 Chiton? spec. nov. Kirkby, 1862:235-236. Rochebrune 1883: 35. Helminthochiton sp. (King). Salter 1847:51 (footnote). Chiton loftusianus King, 1848:12 (nomen nudum?). King 1850: 202-203, pi. 16, fig. 9-14. Roemer in Bronn 1854:447. Howse 1857:463-464. de Koninck 1857:193, 195. Howse 1858: 244, 271-272. Kirkby 1859:607, 611-615, pi. 16, fig. 31- 41. Baily 1859:333; 1860:94. Kirkby 1860:243-248, pi. 13, fig. 31-41; 1864:216. Kirkby and Young 1867:340-341, pi. 16, fig. 17. Etheridge 1882:89. Yochelson 1971:131. Protalochiton loftusianus (King). Rochebrune 1883:3, 8, 36- 37. Cymatochiton loftusianus (King). Dall 1882:282 [type species of Cymatochiton Dall, 1882 by original designation]. Tryon 1 883:340, pi. 85, fig. 68-69. Branson 1 948: 76 1 . Smith 1 960: 154, fig. 36,6a-f (ex King 1850). Yochelson 1971:132. Van Belle 19756: 137, pi. 2, fig. 3a-b. Sirenko and Starobogatov 1977:35, fig. lg, h. Geological Age. — Permian (Magnesian Limestone). Up- per Carboniferous (Orchard Limestone?). Localities. — England: Durham, shell limestone of Tunstall Hill (King); Humbleton Hill, Hylton Castle, and at the New Poorhouse, Bishopwearmouth (Kirkby); Claxheugh, Ryhope, Silksworth, and Southwick Red House (Howse). Scotland: Wil- liam wood, near Glasgow, in shales of the Orchard Limestone. Location of Material. — Specimen from William wood in the collection of J. Bennie (fide Etheridge). Specimens in BM (N.H.) (fide H. W. Ball). Remarks.— The illustrations show this to be a valid polyplacophoran species. The interme- diate valves having a swept-wing appearance with a pointed apex, a rather prominent jugal ridge, and excavated anterolateral margins. The sutural laminae are small and semicircular. The valves measure approximately 1 2 mm long and 6 mm wide. End valves are generally semicircular in shape, with rounded margins; the mucro on the tail valve is near the posterior margin. (It should be mentioned that King's original illustrations of the valves of C. loftusianus [see Smith 1960, p. 153, figs. 36, 6a-f ] do not indicate the presence of sutural laminae in the intermediate and tail valves, and the head and tail valves are reversed in position.) In discussing polyplacophoran valves from the Permian, Howse (1857) said he thought several species were included and doubted whether King's description and illustrations were correct. The species has been reported from several localities in addition to the Permian of Tunstall Hill, the type locality. Kirkby (1859) mentioned and il- lustrated an intermediate valve from the Car- boniferous Lower Scar, Yorkshire, England. Eth- eridge (1882) cited a single intermediate valve from Williamwood, near Glasgow, Scotland, in the Upper Carboniferous shale of the Orchard Limestone. Branson ( 1 948) reported it from Ger- many as well as England. Kirkby (1859:613) covered the species in con- siderable detail. His account adds materially to an understanding of its characters. He had ade- quate material for study as he says "out of ninety- one plates which I have obtained at Tunstall Hill, sixty-three belong to the short, transverse type [=C? cordatus Kirkby, 1859], and fourteen to the more elongate type [=C loftusianus].'''' Kirkby (1862:235-236, fig. 7-8) lists Chiton? sp. nov. based on a single shield-shaped plate, longer than wide, with no indication of sutural laminae. The side view shows a projecting, point- ed apex. The jugal ridge is rather well-developed, the lateral areas are weakly defined, and the dor- sal surface is coarsely granulated in a concentric pattern following the faint lines of growth. Mea- surements are: length, 4/10 in. (10 mm); breadth, 7/20 in. (9 mm). Kirkby said it resembled Chiton barrandeanus de Ryckholt, 1852, from the Car- boniferous of Vise, Belgium, but considered it to be different specifically. Later, in 1867, Kirkby and Young identified this plate as C. loftusianus. It should be noted that this valve is not Chiton sp. nov.? described and illustrated by Kirkby in 1 862 (p. 236, fig. 9-10), which was renamed later as Chiton kirkbyi by de Koninck, 1883. longissimus Bergenhayn, 1955, Chelodes Chelodes longissimus Bergenhayn, 1955:14-15, pi. 1, fig. 5. Sirenko and Starobogatov 1977:31. Geological Age.— Ordovician (Middle Bala). Locality.— Scotland: Shalloch Mill. Location of Material. — Holotype, BM (N.H.) G-47174. Remarks.— The species is based on a single, heart-shaped, intermediate valve 14 mm long and 8 mm wide. It is high-arched, with a well- developed saddle. Bergenhayn compared it with Chelodes gotlandicus Lindstrom, 1884. mempiscus (de Ryckholt, 1845), Gryphochiton Chiton mempiscus de Ryckholt, 1845:48-50, 62, pi. 2, fig. 5- 8. Bronn 1848:292. de Koninck 1857:196. Baily 1859:333; 1860:95. Kirkby 1862:237. Bigsby 1878:319. Gryphochiton mempiscus (de Ryckholt). Dall 1882:280. Rochebrune 1883:25-26. Sirenko and Starobagatov 1977: 35. Helminthochiton mempiscus (de Ryckholt). Salter 1847:52. de Koninck 1883:202-203, pi. 50, fig. 23, 31. Smith 1960:152. Geological Age. — Lower Carboniferous. Locality. — Belgium: Toumai. 40 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 Location of Material. — PSM (fide Rochebrune). On ex- hibit in Paleontological Museum, Paris (fide G D. Hanna). Remarks.— This appears to be a valid poly- placophoran species although Rochebrune (1883) thought it to be conspecific with Gryphochiton priscus (Munster, 1839). mirabilis (Butts, 1926), Chelodesl Priscochitonl mirabilis Butts, 1926:100, pi. 18, fig. 30-31. Chelodesl mirabilis (Butts). Smith in Smith and Toomey, 1 964: 14-15. Geological Age. — Lower Ordovician (Odenville Lime- stone). Locality. — USA: Alabama, about 1.6 km SW of Hebron Church, 8 km SW of Leeds. Location of Material. — Holotype, USNM-71467. Remarks. —The holotype exhibits all the char- acters of the genus Chelodes, to which it is re- ferred provisionally. It measures (in mm): length, 22.8; width, 17.3; height, 13.0; overhang of apex equivalent to the apical area, 10.0. Butts stated that valves were fairly abundant at the type lo- cality. mosensis (de Ryckholt, 1 845), Pterochitorf! Chiton mosensis de Ryckholt, 1845:50, pi. 1, fig. 10. Bronn 1848:292. de Koninck 1857:195. Baily 1859:333; 1860:95. Bigsby 1878:319. Rochebrune 1883:32. Helminthochiton? mosensis (de Ryckholt). Salter 1847:52. Rhombichiton mosensis (de Ryckholt). de Koninck 1883:206, 207. Geological Age. — Lower Carboniferous. Locality. — Belgium: Vise. Location of Material. — Unknown. Remarks. — Both de Koninck and Baily orig- inally thought Chiton mosensis was a variety of C. gemmatus de Koninck, 1844 [=C. subgem- matus d'Orbigny, 1850], although later, in 1883, de Koninck placed it in his new genus Rhom- bichiton as a junior synonym of R. gemmatus (de Koninck, 1883). Dall (1882) curiously omits any mention of C. mosensis. Pending further study of the type and related material, Chiton mosensis would appear to be acceptable as a valid polyplacophoran in spite of Rochebrune's doubt on this point. Proper generic placement must await additional study, but Chi- ton mosensis appears to have characteristics sim- ilar to those of Pterochiton Carpenter in Dall, 1882. mucronatus (de Koninck, 1883) Helminthochiton mucronatus de Koninck, 1883:204, pi. 51, fig. 19-22, 33-35. See: priscus Munster, 1839. Geological Age. — Lower Carboniferous. Locality.— Belgium: Tournai. Location of Material. — Specimens in BM (N.H. partment of Geology (fide H. W. Ball). De- Rem arks.— The specimens of this species, as illustrated and described by de Koninck (1883), are little different from those of Gryphochiton coarctatus (de Koninck, 1883) or G. priscus (Munster, 1839). It appears that the specimens of all three illustrate a normal variation and that the two former species should be considered syn- onyms of G. priscus. nervicanus (de Ryckholt, 1845), Gryphochiton Chiton nervicanus de Ryckholt, 1845:47, 62, pi. 1, fig. 7-9. Bronn 1848:292. de Koninck 1857:196. Baily 1859:333; 1860:95. Kirkby 1862:237. Helminthochiton nervicanus (de Ryckholt). Salter 1847:52. de Koninck 1883:203, pi. 52, fig. 30-33; pi. 53, fig. 8-11. Gryphochiton nervicanus (de Ryckholt). Gray 1847a:70 [type species of Gryphochiton Gray, 18476, by monotypy]. Herr- mannsen 1852:58. Dall 1882:280. Rochebrune 1883:25. Sirenko and Starobogatov 1977:35. Geological Age. — Lower Carboniferous. Locality. — Belgium: Tournai. Location of Material. — PSM (fide Rochebrune). BM (N.H.) (fide H. W. Ball). Specimens on exhibit, Paleontological Mu- seum, Paris (fide G D. Hanna). Remarks. — Rochebrune considered this species to be the same as Chiton priscus Munster, 1839 although both de Koninck and Baily listed it as a separate species. newelli Smith, 1976. Pterochiton Pterochiton newelli Smith, 1976:285-286, fig. 29-34. Sirenko and Starobogatov 1977:36. Geological Age. — Middle Permian. Locality. —USA: Texas. Type locality: "USNM Loc. 726-d; small Leptodus bed at 1484 m elevation, 2.194 km, south 4° west of Willis ranch, and 1.565 km, north 68° east of Hill 5801, Hess Canyon quadrangle, Texas" (Smith 1976). Location of Material. — Holotype, USNM-21 1 133; para- types, USNM-2 1 1 1 34-2 11139. Remarks.— This species from the West Texas Permian is related to Pterochiton arthurcooperi Smith, 1976 although it is much smaller in size. Measurements are (mm): SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 41 Intermediate valves Tail Holotype Another valve Length Width Height 6.2 5.9 3.3 5.4 + 7.1 3.0 3.7 + 4.4 2.0 Contributing to the separation of this species from P. arthurcooperi is the fact that no valves of the latter were recovered from locality 726-d, the type and so far the only locality for P. newelli. occidental is Foster, 1837. Genus incertae sedis Chiton occidentalis Foster, 1837:82-84, fig. 20. Geological Age. — Pennsylvanian. Locality. — USA: Ohio. Limestone in the bed of the Mus- kingum River just below the falls at Zanesville (Foster). Location of Material. — Unknown. Remarks. — From the description and illustra- tion provided by Foster (1837) this specimen appears to be an incomplete internal mold of a nautiloid cephalopod. It is here discounted as a polyplacophoran. ochtinensis (Turek and Prokop, 1982), Proleptochiton Rhombichiton ochtinensis Turek and Prokop, 1982:288-290, pi. 2, fig. 1-2, text-fig. 2. Geological Age. — Middle Carboniferous (Namurian A). Locality. — Quarry northwest of the village of Ochtina in the SpiSsko-gemerske Rudohorie Mts., Czechoslovakia. Location of Material. — Holotype (reg. no. S2205) in the collections of the Paleontological Department, National Mu- seum, Prague. Remarks.— This species is based upon an ar- ticulated specimen of all eight valves. The valves are slightly disturbed in position and the sutural laminae are not observable. Turek and Prokop believe that this species is closely related to Pro- leptochiton laterodepressus (Bergenhayn, 1945) but differs in being smaller, having coarser sculp- ture, and less defined medial areas. The specimen is 9.5 mm long and approximately 3.5 mm wide. The reconstruction of the outline of the tail plate in text-figure 2 appears to be incomplete and based only upon the exposed portion of the plate in this specimen. The anterior margins could not be so posteriorly divergent in relation to the shape of the posterior margins of the recon- structed intermediate valves. oklahomensis Smith in Smith and Toomey, 1 964, Ivoechiton Ivoechiton oklahomensis Smith in Smith and Toomey, 1964: 22-23, pi. 4, fig. 1-15. Van Belle 1975a, pi. 1, fig. 9a-b. Geological Age. — Lower Ordovician (Kindblade Forma- tion). Locality. — USA: Oklahoma, from the lower part of the Kindblade Formation, Mill Creek section, Arbuckle Mts. Location of Material. — Holotype, OU-5219; paratypes, OU-5220, 5221. Paratypes, USNM- 144534, 144535. Para- types, CAS- 12587, 12588. Remarks.— The species is based on seven in- termediate valves, no end valves having been found. The preservation is poor. It has been re- ferred to the genus Ivoechiton from the Upper Cretaceous of Sweden solely because of its gen- eral valve shape and configuration, an assign- ment that must remain provisional until better- preserved specimens can be collected. onerosus, Hoare and Smith, 1984, Stegochitonl Stegochiton? onerosus Hoare and Smith, 1984:99, fig. 10J-M. Geological Age. — Lower Permian (Wolfcampian). Locality.— USA: Texas, Hess Formation, USNM loc. 709d, Glass Mts., West Texas. Location of Material. — Holotype, USNM-330888; para- types, USNM-330889-330891. Remarks.— This species is based upon inter- mediate valves which in general shape are close to that of Stegochiton coxi Hoare and Smith, 1984. Stegochiton? onerosus differs in being very thick-valved with much larger, subtrapezoidal sutural laminae projecting as extensions of the anterolateral margins, and an ornamentation of closely spaced pustules arranged in a quincunx pattern. Measurements of a valve are (mm): length, 15.1; width, 15.0; height, 10.8. orbiculus Trenkner, 1868, "Chiton" Chiton orbiculus Trenkner, 1868:136, pi. 2, fig. 28. Clarke 1885:339, pi. 4, fig. 14-15. Geological Age.— Upper Devonian. Locality.— Germany: Winterberg, Hartz Mts. Location of Material. — Unknown. Remarks.— Clarke believed this species to be a synonym of "cf. Chiton priscus Munst., de Koninck . . . [1883], tome VIII, t. 53, f. 26-28." He gives its dimensions as 14 mm long and 16 mm wide. 42 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 pannuceus, Hoare and Mapes, 19856, Acutichiton Acutichiton pannuceus Hoare and Mapes, 19856:1324-1326, fig. 1.1-1.15. Geological Age.— Upper Pennsylvanian (Virgilian). Locality.— USA: Texas, Finis Shale exposed in gullies south of dam, 0.4 km east of Hwy. 59 and 8.3 km NE of Jacksboro, Jack Co., Texas. Cundifr7'/2-minute Quadrangle. Location of Material. — Holotype, OSU-36976; para- types, OSU-3697 1-36975. Remarks.— This small, thick- valved species (~25 mm long) is based upon one tail, two head, and four intermediate valves. The head valve is semicircular in shape with convex slopes and only slightly mucronate. The intermediate valves are highly arched, slightly wider than long, mu- cronate, with a moderate jugal sinus, and large apical areas. Distinct lateral areas are raised above the central areas and marked by pronounced growth rugosities and finer granulose ornamen- tation. The sutural laminae are relatively narrow and bluntly rounded anteriorly. The tail valve is triangular in shape with a narrow jugal ridge end- ing in a terminal mucro. The posterior area is defined by coarse growth rugosities which extend onto the ventral hypotyche. The sutural laminae are narrow, thick, and broadly rounded. Surface ornamentation is of granules which are finer on the lateral areas than on the central areas of the intermediate valves and on the posterior area of the tail valve. Average dimensions are (mm): Head Intermediate Tail Length Width Height 2.3 5.2 2.2 4.3 5.4 2.7 5.3 3.8 2.6 papilio (Whidborne, 1892), Pterochiton Helminthochiton papilio Whidborne, 1892:333-335, pi. 31, figs. 15, a, b, 16. Geological Age. — Devonian. Locality.— England: Wolborough and Lummaton (Whid- borne, 1892). Location of Material. — Figured specimen (15, a, b) in the Museum of Practical Geology, London. Figured specimen (16) in Whidborne's private collection (fide Whidborne). Remarks. — It is possible that Whidborne (1892) has included two different species under this designation. Figure 16 shows an entirely dif- ferent intermediate valve shape than figures 15, a, b and it is the latter upon which the description of the species is based. He had some doubt as to the biological affinity of the specimen from Lum- maton although it has the general shape of the valve illustrated by Barrois (1889) as Helmintho- chiton lebescontei. The specimen as described and illustrated pos- sesses very large sutural laminae which are ap- parently striated, excavated anterolateral mar- gins, a projecting anterior margin between the sutural laminae, an acuminate posterior margin and steep side-slopes. An ornamentation of oblique, raised ridges may be present. The spec- imen is 16.0 mm long, 14.0 mm wide, and 10.0 mm high. On the basis of the characteristics as described and illustrated we are placing this species in the genus Pterochiton Carpenter in Dall, 1882. parallelus, DeBrock, Hoare, and Mapes, 1984, Coryssochiton Coryssochiton parallelus DeBrock, Hoare, and Mapes, 1984: 1 127-1 129, fig. 2G, H; 6A-0 [type species of Coryssochiton DeBrock, Hoare, and Mapes, 1984, by original designation]. Geological Age. — Middle Pennsylvanian (Desmoinesian). Locality. — USA: Texas, Lazy Bend Formation exposed on a small tributary to Kickapoo Creek, 30 m N of where Farm to Market Road 1189 crosses Rocky Branch, approximately 8.5 km NE of Lipan and 0.75 km S of Kickapoo Falls, Hood Co. Dennis 7'/2-minute Quadrangle. Location of Material. — Holotype, OSU-36930; para- types, OSU-3693 1-36939 and BGSU-4229. Remarks.— A reconstructed specimen is about 22 mm long with a length to width ratio of 3.5: 1 . The head valves are broadly rounded, about twice as wide as long, with a nearly straight pos- terior margin, slightly mucronate, and straight side-slopes. The intermediate valves are low, subrectangular with nearly parallel anterior and posterior margins, rounded lateral margins, slightly mucronate (apical angle averages 126°), and broadly rounded sutural laminae. Tail valves are strongly arched with steep side-slopes, with a sharply rounded posterior margin, mucro lo- cated above posterior margin, and broadly rounded sutural laminae. All valves are excep- tionally thick. The valve surfaces are ornament- ed with rows of very fine granules paralleling the anterior and lateral margins. Average dimensions are (mm): Head Intermediate Tail Length Width Height 2.8 5.7 1.7 3.1 6.1 1.8 3.2 3.4 1.8 SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 43 The new genus Coryssochiton was erected to include taxa having thick valves, subrectangular intermediate valves lacking division into areas, and highly arched tail valves with the mucro located above the posterior margin. The sutural laminae are broadly rounded, not extending to the anterolateral corners. parvus (Stevens, 1858), Gryphochiton Chiton parvus Stevens, 1858:264. Anthrocochiton parvus (Stevens). Rochebrune 1883:30. Gryphochiton"! parvus (Stevens). Cumings 1906: 1365-1 366, pi. 24, fig. 8, 8a-c. Helminthochiton parvus (Stevens). Yochelson and Saunders 1967:12. Glaphurochiton parvus (Stevens). Sirenko and Starobogatov 1977:36. Pterochiton parvus (Stevens). Kues 1978:305-308, pi. 1, fig. 1- 9; pi. 2. fig. 1, 2, 4-7, 9. Hoare and Sturgeon 1979:178, pi. 2, fig. 4-6. Geological Age. — Middle Mississippian (Meramecian). Localities. — USA: Indiana, Bergen Hill (later corrected to Spergen Hill) (Stevens); also Elletsville, Stinesville, Ramona, and Cleveland quarry near Harrodsburg (Cumings; Kues). Location of Material. — Neoholotype, IU 1033-1; neo- paratypes, IU 1033-2, 1669, 1669-B, 8130-1, 13882, 13885, 13890 in the Department of Geology, Indiana University, Bloomington; neoparatypes, USNM-244959-244961. Neo- paratypes, UNM-3130, 3131, in the Department of Geology, New Mexico University, Albuquerque. Specimens in Depart- ment of Paleontology, University of California (Berkeley), no. 1639. Remarks.— This species belongs in the genus Gryphochiton Gray, 1847a. Cumings said Ste- ven's species agrees with specimens in the In- diana University Collection from the Salem Limestone of Harrodsburg, Indiana. Kues (1978) selected the neoholotype from the Harrodsburg locality. Valves of Gryphochiton parvus are much smaller than those of Glaphurochiton carbona- rius (Stevens, 1858) from the Pennsylvanian of Illinois, Missouri, and Pennsylvania. It is a valid species with, apparently, a fairly limited geo- graphic distribution in the United States. patelliformis Etheridge, 1882. Genus incertae sedis Chitonellus(l) patelliformis Etheridge, 1882:98-99, pi. 1, fig. 1 7; pi. 2, fig. 8-9. Geological Age. — Lower Carboniferous (Main or Hurlet Limestone). Locality.— Scotland: Ayrshire, Law Quarry, near Dairy (Etheridge). Location of Material. — Collections of J. Bennie, J. Arm- strong, J. Smith, etc. (fide Etheridge). Present location un- known. Remarks.— This species is based on what is thought to be a head valve, ovate in shape, with a patelliform apex situated anterior to the center of the valve. From this apex, at least seven strong, diagonal ribs radiate to the anterior valve mar- gin, crenulating the valve edge; also, two strong, diagonal grooves radiate posteriorly with a nar- rowly triangular, raised, rounded dorsal area be- tween them. The valve appears to have an ar- ticulamentum consisting only of a narrow rim around the valve margins. There is no evidence of the occurrence of sutural laminae on one spec- imen (Etheridge 1882, pi. 2, fig. 8-9), although in another (pi. 1, fig. 17), a possible tail valve, the presumed articulamentum area, which is rather wide and extends anteriorly, terminates in two rounded projections with a broad, square, shallow sinus between them. Related species are Chitonellus antiquus (Howse, 1848), C. bennieanus Etheridge, 1882, C. subantiquus Kirkby and Young, 1867, and possibly C. distortus Kirkby, 1859, the latter species from the British Permian. The general remarks relating to C. bennieanus apply equally well to C. patelliformis and the species is here rejected as a polyplacophoran. priscoides (Carpenter in Dall, 1882), Gryphochiton Helminthochiton priscoides Carpenter in Dall, 1882:280. No- men nudum. Geological Age. — Devonian. Locality.— Germany: Vilmar, in Hesse Nassau (Prussia), 12.9 km SW of Weilberg. Location of Material. — MCZ (Schultze Collection). Remarks.— Helminthochiton priscoides was merely listed by Dall, based on specimens in the MCZ, Cambridge. These specimens, with others in the Schultze Collection were loaned for study through the courtesy of Dr. Harry B. Whitting- ton, and a manuscript report was prepared, which is unpublished. The Schultze Collection lots are accompanied by labels in P. P. Carpenter's hand- writing and initials. The specimens of H. pris- coides represent a tail valve and a head valve, according to Carpenter, whose label reads: "Sent with Chiton corrugatus Sand, teste Schultze but not congeneric. Devonian. Vilmar. Helmintho- chiton priscoides Cpr. (type)." 44 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 The supposed head valve is flattish, rather thin in texture, with a more or less interrupted con- centric sculpture. It is not complete, especially at the posterior edge. It measures (in mm): length, 18.8; width, 16.1; and height, about 7.0. The back is rounded, with straight side-slopes, and a slightly convex aspect in a longitudinal view. In- ternally there is a strong V-shaped ridge parallel with the posterior valve edges and about 4.5 mm in from these edges. The supposed tail valve seems, without much doubt, to be one. It is high and bluntly carinate, although somewhat crushed in on the right side. The side-slopes are very steep and straight. Lon- gitudinally, the blunt mucro is prominent, with the posterior edge sloping away sharply at first and less so toward the posterior margin. Sculp- ture is somewhat similar to that occurring on the supposed head valve. Gryphochiton priscoides is a nomen nudum as of Dall (1882:280). Until intermediate valves can be found that can be definitely associated with the two available specimens, one would hesitate to consider it a valid species although they appear to be different from any other Paleozoic poly- placophorans so far described. prisms (Miinster, 1839), Gryphochiton Chiton priscus Miinster, 1839:38, pi. 13, fig. 4. de Koninck 1842:321-322, pi. 23, fig. la-d. de Ryckholt 1845:56, 62, pi. 3, fig. 1-9. Geinitz 1846:389. Salter 1847:49, 52, fig. 2. Bronn 1 848:292. d'Orbigny 1850, vol. 1:127. Quenstedt 1852: 445. Quenstedt 1882:681. Roemer in Bronn and Roemer 1851:447, pi. 3, fig. 18. de Koninck 1857:192, 196. Chenu 1859:379, fig. 2852. Baily 1859:333; 1860:95. Eichwald 1860: 1093. Kirkby 1862:237. Roemer 1876, atlas, pi. 45, fig. 22. Bigsby 1878:319. Rochebrune 1883:2, 9. Fraas 1910:83, fig. 55. Chiton (Gryphochiton) priscus Miinster. von Zittel 1924:436, fig. 803. Gryphochiton priscus (Minister). Dall 1882:280 [non] type species of Gryphochiton Gray, 1847a. Rochebrune 1883:25- 26. Tryon 1883:339, pi. 85, fig. 70. Simroth in Bronn 1893: 31 1, fig. 37. Stromer von Reichenbach 1909, fig. 230. Pom- peckj 1912, fig. 1A. Quenstedt 1932:86. Moore, Lalicker, and Fischer 1952:272, fig. 3. Dechaseaux in Piveteau 1952, fig. 3. Sirenko and Starobogatov 1977:35, fig. li, j. Chiton (Helminthochiton) priscus Miinster. von Zittel 1885, fig. 209. Helminthochiton mucronatus de Koninck, 1883:204, pi. 51, fig. 19-22, 33-35. Helminthochiton coarctatus de Koninck, 1883:201-202, pi. 50, fig. 33-36. Helminthochiton priscus (Miinster). Salter 1847:49, 52, fig. 2. de Koninck 1883:199-200, pi. 50, fig. 37, 48; pi. 51, fig, 36; pi. 53, fig. 21, 29. Richardson 1956:62. Smith 1960:152-153, fig. 36,2a-b (ex de Koninck, 1883). Fischer 1957:11-12. Eberzin 1960:15-17, fig. 1. Nicolaus 1963:203, pi. 16, fig. 2a-g. Van Belle 19756:136, pi. 2, fig. la-b. Geological Age. — Lower Carboniferous. Locality. — Belgium: Tournai. ". . . mergligen Lagerns des jungen vebergans-Kalk von Tournay" (Minister 1839); "... a Tournay, dans l'argile subordonee au systeme anthraxifere su- perieur; elles sont rare dans le calcaire mdme" (de Ryckholt 1845). Location of Material.— PSM (de Koninck Collection) (fide P.-H. Fischer). USNM-63400. MCZ (Schultze Collection). Valves on exhibit in the Paleontological Museum, Paris (fide G D. Hanna). Remarks. — Gryphochiton priscus has been the most frequently mentioned of all Paleozoic species. This frequency of record may be because the valves are usually well preserved, or because such specimens have been collected with all eight valves in place, which is a situation of rare oc- currence. Also, it is possible with sufficient ma- terial to make a hypothetical assembly of all valves, which when cemented together, provide a realistic combination. The set of valves in the USNM, which is cited above, comes from Tournai, the type locality. It consists of a presumed series of eight valves of which the first six have been glued together in a presumably normal overlapping position; valves vii and viii are separate and are cemented one on top of the other by the original matrix. In ad- dition, there is a separate head valve, 16 mm wide and 9.7 mm long, and a separate inter- mediate valve, 17.3 mm wide, 15.6 mm long, and 8.8 mm high. Comparison of all these valves with a somewhat comparable series of Grypho- chiton coarctatus (de Koninck, 1883), also in the USNM, reveals no important differences. Thus, unless compelling reasons can be advanced for indicating a different assignment, Helminthochi- ton coarctatus should, for the present, be placed as a synonym of H. priscus. The synonymy of Gryphochiton priscus (Miinster, 1 839) has been somewhat confused by the fact that Guido Sandberger ( 1 842) also named a C. priscus from the Middle Devonian of Vil- mar, Germany, which de Ryckholt renamed Chi- ton sandbergianus in 1845. Dall (1882) desig- nated C. priscus (Miinster, 1839) as the type species of the genus Gryphochiton Gray, 1847a apparently overlooking the fact that Gray had already designated Chiton nervicanus de Ryck- holt, 1845 as the type of his genus (1847a). Rochebrune (1883) placed Chiton nervicanus, C mempiscus de Ryckholt, 1845, and C. turnaci- SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 45 anus de Ryckholt, 1 845 as synonyms of C. pris- cus, but no subsequent reviewer has accepted this assignment. Specimens under the name of Helminthochi- ton priscus from Cork, Flintshire, and Eire, are in the BM (N.H.) (fide H. W. Ball) but it would appear advisable to compare the material with properly identified valves from the type locality to make sure they are actually the same species. Eichwald (1860) said that H. priscus has been found in "l'etage inf. de Borowitchi," on the banks of the Prikscha River in Russia. This identifi- cation also needs confirmation even though Eichwald has said that the specimen, which is in the collection of the Institute of Mines, Lenin- grad, is quite complete and easily identified as the same species from the Carboniferous of Bel- gium. priscus Sandberger, 1842 Chiton priscus Sandberger, 1842:399. de Koninck 1857:196. Baily 1859:333. See: Chiton sandbergianus de Ryckholt, 1845. Remarks. — Realizing that Sandberger's name was preoccupied by Chiton priscus Munster, 1839 de Ryckholt renamed it. procumbens (de Koninck, 1883), Gryphochiton Helminthochiton procumbens de Koninck, 1883:204-205, pi. 51, fig. 45-48. Geological Age. — Lower Carboniferous. Locality. — Belgium: Toumai. Location of Material. — Unknown. Remarks.— Although de Koninck described both intermediate and tail valves of this species, only the former are illustrated. The intermediate valves are subtriangular in shape with the lateral margins curving into convex posterior margins so that there is a continuous curve from the an- terolateral area to the apex. There is a distinct jugal sinus and the sutural laminae are relatively short and blunt. The possible tail valve is de- scribed as wider than long, subelliptical in shape and with a jugal carina extending less than two- thirds the valve length, being raised above the valve surface. The subtriangular shape of the in- termediate valves appears to be distinctive from Gryphochiton priscus (Munster, 1 839) and other species of this genus and the description of the tail valve appears to be more like that of a Pter- ochiton than a Gryphochiton. productus Bergenhayn, 1960, Preacanthochiton Preacanthochiton productus Bergenhayn, 1960:173, fig. 7-8. Geological Age.— Upper Cambrian (Van Buren and Em- inence formations). Locality. — USA: Missouri, Washington County, near the top of the south slope of a hill, 8 km S of Potosi, on the Caledonia Road (Van Buren Formation); Shannon County, ~ 1 m above the porphyry, Jerktail Mine, head of a small tributary of Thompson Creek, 11.3 km NE of Eminence, NE'/i, sec. 5, T 29N, R 3W (low in the Eminence Formation). Location of Material. — Holotype, USNM- 137373, plus additional specimens. Remarks.— This species is based on three tail valves and two fragments, also believed to be tail valves by Bergenhayn. Comments on Preacanthochiton cooperi Ber- genhayn, 1960 and P. aff. cooperi Bergenhayn, 1960, described at the same time, apply equally as well to P. productus. The collection of tail valves only, while possible, seems a bit unusual. pyrmidalus Hoare, Sturgeon, and Hoare, 1972, Acutichiton Acutichiton pyrmidalus Hoare, Sturgeon, and Hoare, 1972:679- 680, pi. 3, fig. 1 5-22 [type species of Acutichiton Hoare, Sturgeon, and Hoare, 1972, by original designation]. Hoare and Sturgeon 1976:841, pi. 2, fig. 1-3. Hoare and Sturgeon 1979:179-180, pi. 1, fig. 1-3; pi. 3, fig. 2. Van Belle 1978: 66. Hoare, Mapes, and Atwater 1983, fig. 1A, 2D, E, 3C, D, 4Q, R. DeBrock, Hoare, and Mapes 1984:1132-1134, fig. 9A-W. Geological Age. — Middle Pennsylvanian (Desmoinesian). Locality. — USA: Ohio. Vanport Shale. Abandoned drift mine, S center sec. 24, T 8N, R 16W, Mulga Quadrangle, Milton Tp., Jackson Co. and also in the Lower Mercer Shale in Ohio. Texas, in the Lazy Bend Formation. Small tributary of Kickapoo Creek, 30 m north of crossing of Farm to Market Road 1 189 and Rocky Branch, approximately 8.5 km NE of Lipan and 0.75 km south of Kickapoo Falls, Hood Co., Texas. Dennis 7'/2-minute Quadrangle. Location of Material. — Holotype, OSU-27158; para- types, OSU-27 159-27 165. Paratypes, BGSU-2744. Remarks.— This species is based on a number of intermediate and tail valves, no head valves having been collected from the type locality. Measurements (length x width) of the largest in- termediate valve are 2.6 x 5.4 mm, and of the largest tail valve, 3.8 x 3.8 mm. It is the first- described species in the genus Acutichiton Hoare, Sturgeon, and Hoare, 1972, characterized by its fine granular sculpture with intermediate valves wider than long and lacking a jugal sinus, or hav- ing a very shallow one; the tail valves are tri- angular with keeled jugal areas, a terminal mu- 46 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 cro, and a large hypotyche. A reconstructed animal has an estimated length of 2 1 mm and a width of 4-5 mm. Specimens of Acutichiton pyr- midalus from the Lazy Bend Formation of Texas closely agree with those from Ohio but attain a larger size. The head valves are semicircular with steep anterior and lateral slopes, a small apex, and a large apical area ventrally. quadratus (Etheridge, 1882), Glyptochiton Chitonellus sp. indet., Etheridge, 1882:97-98, pi. 2, fig. 6-7. Chitonellus quadratus Etheridge, 1882:98. Glyptochiton quadratus (Etheridge). Smith 1971:567, 572. Geological Age. — Lower Carboniferous (Main or Hurlet Limestone). Locality. — Scotland: from the Law Quarry near Dairy, Ayr- shire (Etheridge). Location of Material. — Collection of J. Bennie (fide Eth- eridge). Present location unknown. Remarks.— This species is closest to Chito- nellus subquadratus Kirkby and Young, 1867 from the same area. The illustrations show a sim- ilar type of valve, almost square instead of rect- angular. Other differences between the two species, as given by Etheridge, seem relatively minor; he said he thought the two might be con- specific but "if further researches should prove it distinct it might be called C. quadratus" (Eth- eridge 1882:98). The species is another to be listed under the genus Glyptochiton de Koninck, 1883. raymondi Hoare and Sturgeon, 1976, Arcochiton Arcochiton raymondi Hoare and Sturgeon, 1976:842-843, pi. 1, fig. 1-20; pi. 2, fig. 4-12 [type species of Arcochiton Hoare and Sturgeon, 1976, by original designation]. Hoare and Sturgeon 1979:179-180, pi. 1, fig. 8-10; pi. 3, fig. 3. Hoare, Mapes, and Atwater 1983, fig IB, 2F, 4E, F, 5P. DeBrock, Hoare, and Mapes 1984:1 134, fig. 10A-M. Geological Age. — Middle Pennsylvanian (Desmoinesian). Localities. — USA: Ohio, Vanport Shale. Abandoned drift mine, S center sec. 24, T 8N, R 16W, Mulga Quadrangle, Milton Tp., Jackson Co.; also known from the Putnam Hill Shale and Lower Mercer Shale in Ohio. Location of Material. — Holotype, OSU-30363; para- types, OSU 30351-30362, 30364-30370; topotype, OSU- 34824. Paratypes, BGSU-2744. Remarks.— Valves small, short, and thin. Lat- eral and central areas not separated. Tail valve triangular in shape with a strongly concave keel, seen in lateral profile, which ends in a terminal mucro. Under surface (hypotyche) of the tail valve marked posteriorly by longitudinal ridges of co- alesced granules and a central groove. Valve sur- faces ornamented with small granules arranged in intersecting spiral lines. Reconstructed indi- vidual estimated to be 19.1 mm long and 5.1 mm wide. Average dimensions are (mm): Head Intermediate Tail Length Width Height 2.4 5.9 1.2 2.2 5.2 2.6 3.4 3.1 2.2 Van Belle (1978) placed Arcochiton in syn- onymy with Acutichiton Hoare, Sturgeon, and Hoare, 1972. We disagree with this assignment on the basis of Arcochiton having thinner valves, a strongly concave keel on the tail valve, and longitudinal ridges on the hypotyche of the tail valve. riddlei (Frederickson, 1 962), Glaphurochiton') Helminthochiton sp., Frederickson, 1956:65-66, fig. 1. Helminthochiton riddlei Frederickson, 1962:298-302, fig. 1- 3. Yochelson and Saunders 1967:12. Pterochiton riddlei (Frederickson). Hoare, Sturgeon, and Hoare 1972:675. Geological Age.— Upper Pennsylvanian (Missourian). Locality. — USA: Oklahoma, Ada, in the lower part of the Francis Formation. Location of Material. — Holotype reportedly in Okla- homa Geological Survey Collection, Norman, but unable to locate. Remarks. — Glaphurochiton riddlei is based on a well-preserved specimen with six of the eight valves in place in the matrix. The two posterior valves are missing. The species appears to belong to the same general group as Glaphurochiton car- bonarius (Stevens, 1858). ryckholtianus (Dall, 1882), Pterochiton Cymatochiton ryckholtianus Dall, 1882:282. Nomen nudum. Geological Age. — Lower Carboniferous. Locality. — Belgium: Vise. Location of Material. — Types in MCZ (fide Dall). Remarks. — The pertinent material in the Schultze Collection in the MCZ has been studied. Originally, it was critically examined by P. P. Carpenter. The original label is as follows: "16376. Chiton legiacus de Ryckh. / Carb. / Vise." Also, there is a small accompanying label "Coll. Koninck." The lot consists of three spec- SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 47 imens, one a tiny fragment. Carpenter's note reads as follows: "16376. Pterochiton legiacus, de Ryckh., juv., = gemmatus, pars, de Kon., pi. 23, f. 2, c-d. (a) may be gemmatus, juv. (b) may be Rhyckoltianus, worn. Carb. Vise. These may not be conspecific." Specimen (a), referred to by Carpenter, is a partial intermediate valve. The left sutural lam- ina seems to be present but is poorly defined. This, and the worn, beaded sculpture of the teg- mentum argues for its identification as Ptero- chiton subgemmatus (d'Orbigny, 1850) [=Chiton gemmatus de Koninck (1844), preoccupied]. Specimen (b) is a little more than half of an intermediate valve showing the apex, jugal area, and the typical, rounded sutural lamina on the right side. The dorsal sculpture is not preserved. In all probability this also is P. subgemmatus but such an identification cannot be positive, as Car- penter intimated. The tiny fragment is too small for specific comment. Because Cymatochiton ryckholtianus is a no- men nudum, introduced by Dall and not sub- sequently validated by any author, and because the material on which the name apparently is based is too poorly preserved and insufficient for positive identification, the specific name should be dropped and the specimens assigned to Pter- ochiton. sagittalis (Sandberger and Sandberger, 1856). Genus incertae sedis Chiton fasciatus Sandberger, 1842:399. Nomen nudum, de Ryckholt 1845:62. Salter 1847:49. Bronn 1848:292. de Ko- ninck 1857:192. Baily 1859:333; 1860:92 (and footnote). Rochebrune 1883:22-23. Chiton sagittalis Sandberger and Sandberger 1856:239-240, pi. 26, fig. 23, 23a-b. de Koninck 1857:192 (footnote), 196. Baily 1859:333; 1860:92. Dall 1882:283. Rochebrune 1883: 22-23. Beloplaxus sagittalis (Sandberger and Sandberger). Oehlert 1881:17 [type of Beloplaxus Oehlert, 1 88 1 , by original des- ignation]. Fischer 1885:878-879. Etheridge 1897:68. Iredale and Hull 1926:326; 1927:141. Smith 1960:172. Geological Age. — Middle Devonian (Stringocephalen- kalk). Locality.— Germany: Vilmar, in Hesse-Nassau. Location of Material. — Unknown. Remarks.— A review of Sandberger (1842) shows that Chiton fasciatus is a nomen nudum. De Koninck (1857) says that the Sandbergers changed the species name to Chiton sagittalis in 1856 without stating any reason why the older name was dropped. Oehlert (1881) makes C. sagittalis the genotype of his genus Beloplaxus. Questions have been raised about the validity of Beloplaxus sagittalis as a polyplacophoran. Dall (1882) listed it with species "not found to be chitons or chitonoid." Rochebrune believed it to be a cirripede in the family Lepadidae or the septum of a Cyrtina. Fischer, as well as Ire- dale and Hull, expressed views that it was a doubtful polyplacophoran. On the other hand, Etheridge seemed to have little doubt of its poly- placophoran relationship, believing that the gen- era Beloplaxus, and Sagmaplaxus as well, should properly be identified as polyplacophorans. The Schultze Collection in the MCZ contains a series of six fragments with the following label: "Chiton sagittalis Sandb. / Devonian / Vilmar." There is an accompanying note in P. P. Carpen- ter's handwriting, which reads as follows: "Chi- ton sagittalis Sandb., teste Schultze. Devonian. Vilmar. Dr. Dawson and I think they are Le- pads." The fragments are fair-sized, showing a diagonally corrugated sculpture. It is obvious, as it was to Carpenter and Dawson, that they are not polyplacophorans but barnacle remains, per- haps referable to the genus Turrilepas. The original figures in Sandberger and Sand- berger (1856) are drawings, which show a side view of an intermediate valve, with top and bot- tom views of the same valve. It is extremely swept-wing or arrow-shaped in aspect with a length to width ratio of 3:2 and a height to width ratio of 3: 1 . The posterior sinus is V-shaped and has a depth of one-third the valve length. The ventral view shows a well-developed apical area, widest along the median line, becoming more narrow posteriorly and extending almost the full length of the valve on each side. There is no evidence of sutural laminae. Beloplaxus sagittalis is rejected as a polypla- cophoran for the purpose of this study. sandbergianus (de Ryckholt, 1 845), Pterochiton Chiton priscus Sandberger, 1842:399 [non] C.priscus Miinster, 1839. de Koninck 1857:196. Baily 1859:333; 1860:95. Rochebrune 1883:21. Chiton sandbergianus de Ryckholt, 1845:62 [new name for C. priscus Sandberger, 1842, preoccupied]. Bronn 1848:292. de Koninck 1857:196. Baily 1859:333; 1860:95. Rochebrune 1883:21. Pterochiton sandbergianus? (de Ryckholt). Dall 1882:281. 48 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 Geological Age. — Middle Devonian. Locality.— Germany: Vilmar, in Hesse-Nassau, 12.9 km SW of Weilberg, Prussia. Location of Material. — MCZ (Schultze Collection). Remarks.— De Koninck considered Chiton sandbergianus to be the same as C. corrugatus Sandberger and Sandberger, 1853, C. cordifor- mis Sandberger, 1845, and C. priscus Sandber- ger, 1 842. Dall placed it in the genus Pterochiton with a question as to its proper identification. Rochebrune placed both C. priscus and C. sand- bergianus in the synonymy of C. corrugatus. Thus, there is considerable doubt about the validity of the species. The Schultze Collection in the MCZ contains a single specimen accompanied by a note in P. P. Carpenter's handwriting, as follows: "Sent as part of "Chiton corrugatus, Sandb.' teste Schultze. Devonian. Vilmar. Not conspecific. IPterochiton ? Sandbergianus, De Ryckh." This specimen, which is a small, incomplete one, appears to be a well-preserved intermediate valve measuring about 10 mm long, 8 mm wide, and 6.5 mm high. Externally the valve is steep-sided with a rather sharp jugal ridge and well-defined, raised lateral areas. Sutural laminae, if they were pres- ent in life, are not preserved. sarthacensis (Oehlert, 1881), Chelodes? Sagmaplaxus sarthacensis Oehlert, 1881:15-17, pi. 2, fig. 3, 3a-b [type species of Sagmaplaxus Oehlert, 1 88 1 , by original designation]. Rochebrune 1883:5 (footnote), 23 (footnote). Fischer 1885:878. Etheridge 1 897:68. Iredale and Hull 1 926: 326; 1927:141. Geological Age.— Lower Devonian. Locality. — France: Sarthe. Location of Material.— Unknown. Remarks. — Rochebrune thought this species might be a cirripede in the family Lepadidae. Iredale and Hull also expressed doubts that it was a polyplacophoran. Lindstrom, on the other hand, believed it to be a polyplacophoran equal or close to the genus Chelodes; he also expressed the view that the genera Sagmaplaxus and Be- loplaxus were closely related. Etheridge stated that the two taxa were not congeneric, a view adopted in the Treatise on Invertebrate Paleon- tology (Smith 1960). Original material of both genera needs to be studied further before a final judgement can be made on the most likely systematic position of Chelodes? sarthacensis. scaldianus de Ryckholt, 1845. Genus incertae sedis Chiton scaldianus de Ryckholt, 1845:46-47, pi. 1, fig. 4-6. Salter 1847:50, 52. Bronn 1848:292. Kirkby 1862:237. de Koninck 1883:211. Rochebrune 1883:32. Jaekel 1900:13. ICymatochiton scaldianus (de Ryckholt). Dall 1882: 282. Geological Age. — Lower Carboniferous. Locality.— Belgium: Tournai, ". . . dans l'argile subordinee ou systeme anthraxifere superieur de Tournay" (de Ryckholt). Location of Material. — Unknown. Remarks.— This species is based on two spec- imens, one with a length of 17 mm. Dall (1882) thought it had crustacean features. Rochebrune (1883) believed it might be a brachiopod in the genus Spirifer or a crustacean near Philipsia. Based on this evidence, Chiton scaldianus probably is not a polyplacophoran. secundus Horny in Spinar, 1965, Helminthochiton? Helminthochiton? secundus Horny in Spinar, 1965:320, fig. VIII-9. Geological Age. — Lower Devonian (Koneprusy Lime- stone). Locality.— Czechoslovakia (locality unknown). Location of Material. — In "Muzea v Praze" (fide Horny). Remarks.— The specimen in the Natural His- tory Museum of Prague was labeled by the late Professor-Director Jaroslav Perner as "Chiton? secundus Barr. sp." and appears to be a manu- script name (fide R. Horny). The illustration in Spinar (1965, fig. VIII-9) shows characteristics of Helminthochiton, but the preservation leaves questions as to the exact generic determination. sellaefor mis (Butts, 1926), Chelodes Priscochitonl sellaeformis Butts, 1926:125, pi. 31, fig. 7. Chelodes! sellaeformis (Butts). Smith in Smith and Toomey 1964:14. Geological Age. — Middle Ordovician (Chickamauga Limestone). Locality. — USA: Alabama, Birmingham. From the Chick- amauga Limestone, Black River horizon, Mountain Terrace. Location of Material. — Holotype, USNM-71523. Remarks.— The U.S. National Museum lot consists of two specimens, the larger measuring: length, 10.9 mm; width, 9.0 mm; height, 6.9 mm; overhang of apex (mucro), ~4.2 mm. It is not certain whether the specimens are intermediate or tail valves. The species was described at the same time as Chelodes? mirabilis (Butts, 1926) SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 49 from the Lower Ordovician Odenville Lime- stone and the two appear closely related although the valves of C? sellaeformis are smaller. For the present, at least, this species may be assigned to the genus Chelodes. settlensis Rochebrune, 1883, Protalochiton Chiton? sp. Kirkby, 1862:236, fig. 7-8. Protalochiton settlensis Rochebrune, 1883:31 [new name; type species of Protalochiton Rochebrune, 1883 by monotypy]. Smith 1960:173, figs. 45,3a-b (ex Kirkby). Geological Age. — Lower Carboniferous (Lower Scar). Locality. — England: near Settle, Yorkshire, in the Lower Scar Limestone. Location of Material. — Unknown. Remarks.— Protalochiton settlensis is based on a single, shield-shaped valve that is longer than wide. It has the shell areas of the family Lepi- dopleuridae but as the articulamentum of the described valves is evidently not preserved, the systematic position of the species must remain indeterminate pending the collection and study of more and better material from the type lo- cality. silurica BischofT, 1981, Cobcrephora Cobcrephora silurica BischofT, 1981:189-191, pi. 1, fig. 1-16; pi. 2, fig. 18-29; pi. 4, fig. 42-43; pi. 5, fig. 44-46; pi. 6, fig. 47-48; pi. 7, fig. 51-56; text-fig. 5-6 [type species of Cob- crephora BischofT, 1981, by original designation]. Geological Age. — Upper Ordovician to Upper Silurian. Localities.— Australia. Types from limestone lenses in the Panuara Group southeast Cobblers Creek, Cobblers Creek area, approximately 30 km southwest of Orange, New South Wales. Also from the Bridge Creek Limestone along Bridge Creek, approximately 25 km southwest of Orange; Quarry Creek Limestone (type section) on south bank of Quarry Creek about 2 1 km west of Orange; Boree Creek Formation and Borenore Limestone 1 km west of Borenore Caves, approximately 22 km west northwest of Orange; Kildrummie Formation along south bank of Campbells River, 1 1 km south of Rockley, New South Wales; and, Cuga Burga volcanics, 4.5 km southeast of Wellington, New South Wales. Location of Material. — Holotype (SMF 34371) and fig- ured paratypes (SMF 34372-34397) deposited in the Sencken- berg Museum, Frankfurt am Main, Republic of West Ger- many. Remarks.— Valves composed of alternating lamellae of organic and apatitic material. Teg- mentum and hypostracum layers apparently present. Head valve rhomboidal, folded under at posterior apex. Intermediate valves sphenoi- dal to trapezoidal in shape, longer than wide, with two subparallel jugal ridges and sutural lam- inae present. Tail valve acutely triangular, longer than wide and arched longitudinally and later- ally. Ranges of valve measurements (as given by BischofT) (mm): Length Width Head Intermediate Tail 0.80-3.10 0.36-5.95 0.44-5.65 0.63-3.00 0.17-2.70 0.27-1.40 Length of a reconstructed individual, containing seven valves (BischofT, 1981, text-fig. 6) is given as 15.0-33.0 mm. The 7-valved reconstruction was based in part upon Bergenhayn's (1955) in- terpretation of Septemchiton which has been shown to be erroneous by Rolfe (1981). The valve microstructure appears to be poly- placophoran in nature and the ratio of three valve types appears to be consistent with this inter- pretation. The phosphatic composition is radi- cally different from previously described taxa. If correct, it helps to substantiate the notion that phosphatic skeletal structures are intermediate in evolutionary position between nonshelled and calcareous mollusks. The erection of a new ge- nus, Cobcrephora, new family, Cobcrephoridae, and new order, Phosphataloricata by BischofT was necessary to accommodate these forms in the classification of the Polyplacophora. cf. silurica BischofT, 1981, Cobcrephora Cobcrephora cf. silurica BischofT, 1981:191-192, pi. 2, fig. 17, 30. Geological Age.— Lower Silurian. Localities.— Australia. Bridge Creek Limestone along Bridge Creek, about 25 km southwest oT Orange, New South Wales. Limestone in Panuara Group, southeast Cobblers Creek, Cob- blers Creek area, approximately 30 km southwest of Orange, New South Wales. Location of Material. — Figured specimens (SMF 34398- 34399) deposited in the Senckenberg Museum, Frankfurt am Main, Republic of West Germany. Remarks.— Two valves, which are different in outline from those included in Cobcrephora silu- rica BischofT, 1981, are included here. One is broader posteriorly than normal, the other broadly heart-shaped. Both apparently have the phosphatic composition of other taxa in Cob- crephora. simplex (Raymond, 1910), Gryphochiton Glaphurochiton simplex Raymond, 1910:153-154, pi. 24, fig. 50 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 1 1-12; pi. 28, fig. 14. Raymond 191 1:84, 96, pi. 3, fig. 1 1- 12. Cossman and Pissaro 1912:217. Helminthochiton simplex (Raymond). Smith 1960:152. Yo- chelson and Saunders 1967:12. Hoare, Sturgeon, and Hoare 1972:679, pi. 2, fig. 7-16. Hoare and Sturgeon 1976:841, pi. 2, fig. 19, 20. Hoare and Sturgeon 1979:179-180, pi. 1, fig. 4-7; pi. 3, fig. 1. DeBrock, Hoare, and Mapes, 1984:1 1 29- 1131, fig. 2K, L, 8A-S. Gryphochiton simplex (Raymond). Sirenko and Starobogatov 1977:35. Geological Age. — Pennsylvanian. Locality. — USA: Pennsylvania, from the Vanport Lime- stone, Allegheny Group. From old quarries of Green, Marquis, and Johnson, between New Castle and New Castle Junction (Raymond). Ohio, Lower Allegheny, in the Putnam Hill Lime- stone and the Vanport Shale (Hoare, Sturgeon, and Hoare). Texas, from the Lazy Bend Formation (DeBrock, Hoare, and Mapes). Location of Material. — Holotype, CM 1 1 1 and paratype, CM 1 1 2 in the Carnegie Museum, Pittsburgh. Hypotypes OSU- 27134-27142, 36046-36064 and BGSU-4227. Remarks.— Raymond (1911) reported Gry- phochiton simplex from New Castle, Pennsyl- vania, old quarries of Green, Marquis, and John- son, between New Castle and New Castle Junction, in the Vanport Limestone. Hoare, Sturgeon, and Hoare (1972) provided a recent description and excellent illustrations of the species. Their valve measurements are (mm): Head valve Intermediate valves Tail valves Length Width Length* Width Length* Width 3.5 6.5 5.5 5.5 7.0 8.0 4.5 7.0 10.0 7.5 6.6 6.6 7.2 7.0 7.5 6.8 * Not including the length of sutural laminae. Numerous specimens from the Lazy Bend For- mation in Texas are closely similar to those in Ohio and Pennsylvania (DeBrock, Hoare, and Mapes 1984). solenoides Young and Young in Young, 1868, Solenocaris Solenocaris solenoides Young and Young in Young, 1868:171- 173, pi. 1, fig. 7a, b. Rolfe 1981:677, text-fig. 3. Helminthochiton grayiae Woodward, 1885. Reed 1907:1 13— 114, pi. 4, fig. 8. Geological Age.— Upper Ordovician (Caradoc). Locality. —Scotland: Balclatchie Group, Penwhapple Glen, near Girvan, Ayrshire (Rolfe). Location of Material. — Location of original specimen un- known. That figured by Reed (1907) and Rolfe (1981) in BM (N.H.) 20268a. Remarks.— This species was originally thought to be a crustacean by Young and Young in Young (1868). Reed (1907) agreed with Woodward (1885) that forms of this type belonged to the genus Helminthochiton Salter in McCoy, 1846. Subsequent restudy by Rolfe (1981) showed the presence of eight valves and the relationship to Solenocaris Young and Young in Young, 1868. Rolfe noted the presence of a greatly elongated tail valve as distinguishing Solenocaris from Septemchiton Bergenhayn, 1955. Rolfe in Mor- ris (1967) had previously placed Septemchiton Bergenhayn, 1955 in synonomy with Solenoca- ris. sluseanus (de Ryckholt, 1845) Chiton sluseanus de Ryckholt, 1845:55, 62. Bronn 1848:292 (as "sluceanus"). Helminthochiton! sluseanus (de Ryckholt). Salter 1847:52. Kirkby 1862:237 (as "sluceanus"). Bigsby 1878:319(as"s/u- zeanus"). IPterochiton sluseanus (de Ryckholt). Dall 1882:281. Anthracochiton sluseanus (de Ryckholt). Rochebrune 1883:29. Rhombichiton sluseanus (de Ryckholt). de Koninck 1 883:206- 207. See: subgemmatus d'Orbigny, 1850. Geological Age. — Lower Carboniferous. Locality. — Belgium: Vise. Location of Material. — MCZ (Schultze Collection). Prob- ably also in PSM. Remarks.— De Ryckholt's illustrations show a granulated intermediate valve with a marked overhang at the apex and rather large, rounded sutural laminae, not markedly different from de Koninck's figures of his Chiton gemmatus [=C. subgemmatus d'Orbigny, 1850]. Dall (1882) said de Ryckholt's plate 4, figures 7-8 are actually Chiton eburonicus and that de Koninck failed to recognize this in his 1857 review. De Koninck (1883) thought R. sluseanus to be conspecific with R. gemmatus [= subgemmatus]. The Schultze Collection in the MCZ contains several lots of valves involving this species name. In P. P. Carpenter's notes on them it is plain he thought they should be identified as Chiton gem- matus, or at least a variety of gemmatus. From the above, until further evidence to the contrary turns up, it would appear best to place Chiton sluseanus in the synonymy of Pterochiton subgemmatus (d'Orbigny, 1850). soleaformis (Etheridge, 1882), Soleachiton Chiton soleaformis Etheridge, 1882:92-93, pi. 1, fig. 18-19. SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 51 Soleachiton soleaformis (Etheridge). Hoare and Smith 1984: 90. Geological Age. — Lower Carboniferous (Main or Hurlet Limestone). Locality. — Scotland: Law Quarry, near Dairy, Ayrshire. Location of Material.— Collection of J. Bennie (fide Eth- eridge). Present location unknown. Remarks.— Because of the peculiar aspect of this species, Etheridge's description follows: Acutely triangular, slipper-like, elongate, prolonged back- wards into a fine drawn-out point, sharply carinate in the median line, arched. Front margin excavated, arched; apophyses very delicate, simply projecting forwards, not continued laterally along the anterior margin. Surface mi- croscopically granulated in transverse lines; no separation into areas by diagonal lines. On the lower surface there is an elongately triangular, flattened, incurved area, extend- ing from the pointed posterior extremity, somewhat less than half the length of the plate, and with an unorna- mented surface. Interior, shoe-like. The name is derived from solea, a sandal or slipper, spelled solaeformis incorrectly by Eth- eridge (1882:93 and in the plate explanation, p. 105). Although no dimensions of the valve are given, if the scale of Etheridge's illustrations is correct the valves are quite small, with a length of 2.75 mm and a maximum width of about 1.7 mm. On the ventral side the posterior pocket and the narrow sutural laminae are departures from the usual configuration of polyplacophoran valves, approximated somewhat by species in the genus Chelodes and in the genus Priscochiton for head valves only. Neither Etheridge nor Kirkby, with whom the former discussed these fossils, had any doubts about their polyplacophoran re- lationship. 36045. Paratypes, BGSU-2743 and other specimens, BGSU- 4226. Remarks.— This species, from the type local- ity, where it is stated to be abundant, has the following measurements (mm): Head Intermediate Tail Length Width Length Width Length Width Largest Smallest 2.5 4.8 1.5 2.6 4.4 6.5 2.2 4.1 3.2 4.9 1.1 1.8 It is a relatively small species, differing from Gla- phurochiton carbonarius (Stevens, 1858) in the following characters: the subtrapezoidal outline of the tail valve, the short keel and elevated mu- cro of the tail valve, and the short length of the intermediate valves. Specimens from the Lazy Bend Formation in Texas are slightly larger and thicker valved than those from the Vanport of Ohio (DeBrock, Hoare, and Mapes, 1984). Euleptochiton spatulatus lacks the excavated anterolateral areas of Pterochiton. It, and a sim- ilar species, E. tholus, Hoare, Mapes, and At- water (1983), and an undescribed species from the Virgilian of Texas have much finer orna- mentation than that found in Glaphuwchiton Raymond, 1910 and Proleptochiton Sirenko and Starobogatov, 1977. A new generic designation, Euleptochiton, was proposed for these taxa by Hoare and Mapes (1985:875) with P. spatulatus as type species. The genus is distinguished by having high arched valves, fine granulated or- namentation, broad and protruding sutural lam- inae, and a subtrapezoidal tail valve with the elevated mucro at the end of a short jugal ridge. spatulatus (Hoare, Sturgeon, and Hoare, 1972), Euleptochiton Pterochiton spatulatus Hoare, Sturgeon, and Hoare, 1 972:678- 679, pi. 3, fig. 1-14 [type species of Euleptochiton Smith and Hoare, designated herein]. Hoare and Sturgeon 1979:179- 180, pi. 1, fig. 11-15; pi. 3, fig. 4. DeBrock, Hoare, and Mapes 1984:1 129, fig. 21, J, 7A-Y. Geological Age. — Middle Pennsylvanian (Desmoinesian). Locality. — USA: Ohio. Vanport Shale. Abandoned drift mine, S center sec. 24, T 8N, R 16W, Mulga Quadrangle, Milton Tp., Jackson Co., Texas, in the Lazy Bend Formation. Small tributary of Kickapoo Creek, 30 m north of crossing of Farm to Market Road 1 189 and Rocky Branch, approximately 8.5 km NE of Lipan and 0.75 km south of Kickapoo Falls, Hood Co. Dennis 7'/2-minute Quadrangle. Location of Material. — Holotype, OSU-27144; para- types, OSU-27 145-27 157, and other specimens OSU-36002- spinus Yii, 1984, Luyanhaochiton Luyanhaochiton spinus Yii, 1984:25, pi. 1, fig. 8, 9. Geological Age. — Lower Cambrian (Meishucun). Locality.— China: Zhongyicun Member, Dengying For- mation in eastern Yunnan Province. Location of Material. — Holotype 84135, Nanjing Insti- tute of Geology and Palaeontology, Academia Sinica. Remarks.— This species is described by Yii (1984) as follows: "Shell minute-sized, elliptical and high-arched. Head valve semicircular. In- termediate valves wider than long. Tegmentum appearing to be weak developed areas, with an empty spine in the middle part. Ornamentations not well preserved, except for the micro-gran- ules." 52 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 This silicified holotype, consisting of a head and two intermediate valves, is 0.88 mm long and 0.52 mm wide. Yu assigned the genus to a new family Yangtzechitonidae. The spinose character of the intermediate valves is diagnos- tic. No evidence of sutural laminae or insertion plates present. squarrosus, DeBrock, Hoare, and Mapes, 1984, Camptochiton Camptochiton squarrosus DeBrock, Hoare, and Mapes, 1984: 1 1 20-1 1 23, fig. 2A, B, 3A-U [type species of Camptochiton DeBrock, Hoare, and Mapes, 1984, by original designation]. Geological Age. — Middle Pennsylvanian (Desmoinesian). Locality. — USA: Texas, Lazy Bend Formation exposed on a small tributary to Kickapoo Creek, 30 m N of where Farm to Market Road 1 189 crosses Rocky Branch, approximately 8.5 km NE of Lipan and 0.75 km S of Kickapoo Falls, Hood Co. Dennis 7'/2-minute Quadrangle. Location of Material. — Holotype, OSU-35957; para- types, OSU-35958-35973 and BGSU-4223. Remarks.— A reconstructed specimen is about 30 mm long with a length to width ratio of 2:1. The head valves are high and steep-sided, with a mucronate apex and a large apical area. The intermediate valves are swept-winged (apical an- gle averages 131°), twice as wide as long, a sharp jugum, slightly concave side-slopes, a large apical area, and short, broad sutural laminae that ex- tend around the anterolateral corner as unslit insertion plates. The tail valves are suboval in shape with a steeply concave posterior slope be- low the mucro, which is located posterior to mid- length; the short and broad sutural laminae ex- tend well onto the lateral margins as unslit insertion plates. The valve surfaces are orna- mented with coarse granules arranged in radiat- ing rows from apex or mucro. Average valve dimensions are (mm): Head Intermediate Tail Length Width Height 3.6 7.7 2.5 3.5 7.0 2.5 3.2 6.1 1.6 The new genus Camptochiton was erected to include taxa which are intermediate between forms lacking insertion plates and those with slit- ted insertion plates. The extension of the sutural laminae onto the lateral valve margins appears to be a prelude to the development of separate slitted insertion plates. subantiquus Kirkby and Young, 1867. Genus incertae sedis Chitonellus? subantiquus Kirkby and Young, 1867:341, pi. 16, fig. 12a-b, 13. Etheridge 1882:98-99. Geological Age. — Lower Carboniferous (Lower Scar). Locality.— England: Settle, Yorkshire, at base of Lower Scar, Mountain Limestone. Location of Material. — Unknown. Remarks.— The species is based on two pa- telliform plates approaching the configuration of Chitonellus antiquus (Howse, 1848) from the Permian. The description of a nearly perfect, supposed intermediate valve is as follows: Conical, sub-pentagonal in marginal outline, apex re- curved and placed rather behind the centre of the plate. Several fine ribs radiate from the apex down each side, and others appear to have originally existed in front and behind, but are not now visible on this specimen, owing to the imperfect preservation of the shell in these parts. Surface marked with strong lines of growth; length rather under three-eighths of an inch [9.5 mm]; breadth rather over two-eighths of an inch [6.5 mm]. Etheridge ( 1 882) believed his Chitonellus? pa- telliformis was clearly allied with C ? subantiquus "but is distinguished by the lateral position of the radiating ridges in the latter, and other minor characters." It seems clear that both C. patelli- formis and C. subantiquus should be rejected as polyplacophorans until compelling reasons for changing this status are developed. subgemmatus (d'Orbigny, 1850), Pterochiton Chiton gemmatus de Koninck, 1844:323, pi. 23, fig. 2a-e [non] C. gemmatus de Blainville, 1825. de Ryckholt 1845:59-60, pi. 4, fig. 1-4. Bronn 1848:292. d'Orbigny 1850:127. de Koninck 1857:195. Baily 1859:333; 1860:95. Kirkby 1862: 237. Bigsby 1878:319. Etheridge 1897:69. Dunlop 1915:168- 169, pi. 22, fig. 4. Dunlop 1922:75. Bergenhayn 1945:389. Chiton sluseanus de Ryckholt, 1845:55, 62. Bronn 1848:292 (as " sluceanus"). Helminthochiton gemmatus (de Koninck). Salter 1847:52. Helminthochitoril sluseanus (de Ryckholt). Salter 1847:52. Kirkby 1862:237 (as "sluceanus"). Bigsby 1878:3 19 (as "s/u- zeanus"). Pterochiton gemmatus (de Koninck). Dall 1882:281. Pompeckj 1912:355, fig. 2a, b. Fischer 1957:12-13. Sirenko and Sta- robogatov 1977:36. ? Pterochiton sluseanus (de Ryckholt). Dall 1882:281. Anthracochiton gemmatus (de Koninck). Rochebrune 1883: 27-28, pi. 3, fig. 13. Anthracochiton sluseanus (de Ryckholt). Rochebrune 1883:29. Rhombichiton gemmatus (de Koninck). de Koninck 1883:206, pi. 51, fig. 3-10, 28-31; pi. 52, fig. 1-17, 22-29. Rhombichiton sluseanus (de Ryckholt). de Koninck 1 883:206- 207. SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 53 Chiton subgemmatus d'Orbigny, 1850:127 (new name for C. gemmatus de Koninck, 1 844; [non] C. gemmatus de Blain- ville, 1 825, a Recent species]. Rhombichiton subgemmatus (d'Orbigny). de Koninck 1883: 207. [non] Helminthochiton aff. gemmatus (de Koninck). Schmidt 1951:189, 190, pi. 13, fig. 11. Geological Age. — Lower Carboniferous. Localities. — Belgium: Vise. England, Settle, Yorkshire. Scotland: Woodmill, Fife, Strathaven-on-Avon. Location of Material. — PSM (de Koninck Collection) (fide P.-H. Fischer). Specimens under the name Rhombichiton gem- matus (de Koninck, 1 842) from Belgium and from Fife, Scot- land, in BM (N.H.) (fide H. W. Ball). MCZ (Schultze Collec- tion). Specimens from Woodmill, Scotland in USNM. Remarks. — Chiton gemmatus was stated by de Koninck to be a fine, large species extremely rare in the Carboniferous limestone of Vise, Bel- gium, which is the type locality. The above syn- onymy is complicated by the fact that de Ko- ninck's name was preoccupied, a situation recognized by d'Orbigny in 1850; d'Orbigny's rectification of the name was not accepted by de Koninck and was overlooked by subsequent au- thors, several of whom complicated the situation further in their taxonomic treatments. De Koninck (1857) considered four of de Ryckholt's species described in 1845 — Chiton mosensis, C viseticola, C legiacus, and C. ebu- ronicus— to be conspecific with his C. gemmatus, bracketing them under a single number in his list of fossil species. Baily (1859) did the same in his translation of de Koninck's paper. In 1883, how- ever, de Koninck listed Rhombichiton subgem- matus as a synonym of R. gemmatus, the reverse being correct, and in addition, he then included R. mosensis; R. eburonicus; R. slusianus [sic], all ofdeRyckholt(1845); R. sluceanus Bronn, 1848; and Chitorf! sp. nov. Kirkby, 1 862 as synonyms. Dall (1882) referred to "gemmatus (Koninck) Ryckholt, 1845 ... p. 59, no. 13, pi. 4, figs. 1, 2, 3, (fig. 4 forsitans exclus)." Rochebrune (1883) made "gemmatus Kon., 1842-44" and "gem- matus (part) Ryckh., 1845" synonyms of Chiton subgemmatus. In discussing this species most authors base their identifications on specimens from Vise, Belgium. Dunlop (1915) discussed and illustrat- ed what appears to be a cast of the ventral side of a polyplacophoran valve from Woodmill, Fife, in southern Scotland, found at Gallowhill, near Strathaven, which he identified as "Chiton gem- matus." This specimen, he said, was lost in a fire, which is just as well, since the inside casts of polyplacophoran valves are practically useless in identification. Dunlop said C. gemmatus oc- curs near Woodmill "large and in good preser- vation and is the most plentiful." He pointed out that Etheridge (1882:91) showed the Strathaven specimen to be doubtfully identified as C. gem- matus on account of differences in valve shape and other characters. Dunlop's specimens were compared with de Koninck's figures of C. gem- matus by Dr. Wheelton Hind, who pronounced them as being identical. Later, in 1922, Dunlop considered C. gemmatus, C armstrongianus, and C. cordatus to be conspecific, based on valves collected near Woodmill. Two small, imperfect intermediate valves from Woodmill, Dumferm- line, Scotland, are in the collection of the USNM. The identity of fossil polyplacophoran valves from England and southern Scotland with those of the true C subgemmatus of Belgium does not appear to rest on sound ground. Comparison of them with actual type material in the PSM, rath- er than illustrations of them, would seem nec- essary. The large and heavy sutural laminae and the general shape of the intermediate valves suggest that this species should be assigned to Pterochi- ton Carpenter in Dall, 1882 as broadly defined. subgranosus Sandberger, 1 842 Chiton subgranosus Sandberger, 1842:399. Nomen nudum. See: corrugatus Sandberger and Sandberger, 1856. subquadratus (Kirkby and Young, 1867), Glyptochiton Chitonellus subquadratus Kirkby and Young, 1867:342, pi. 16, fig. 5. Etheridge 1882:96-97, pi. 2, fig. 4-5. Young 1878: 324. Glyptochiton subquadratus (Kirkby and Young). Smith 1971: 567, 572. Sirenko and Starobogatov 1977: 37. Geological Age.— Carboniferous. Locality. — Western Scotland: Lower and Upper Lime- stone, Craigenglen, Campsie, Ayrshire (Kirkby and Young); Law Quarry, near Dairy, Ayrshire (Etheridge). Location of Material. — Collection of J. Bennie (fide Eth- eridge). Present location unknown. Remarks.— The species is based on a single, supposed intermediate valve, with the anterior margins ridged and forked, terminating in point- ed projections. The illustration shows sinuses at each end of the valve. The exposed valve area is heart-shaped, occupies about one-fifth of the to- tal valve area, is slightly elevated, and granulated around the margin. Numerous delicate striae 54 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 fringe the heart-shaped area on the dorsal valve surface, which presumably is buried in the man- tle of the animal in life. Dimensions are: length, Va inch (6.4 mm); breadth, V» inch (3.2 mm). Etheridge reported another, similar valve from a slightly different locality, which he illustrated. Chitonellus subquadratus is a unique type of polyplacophoran in the Paleozoic related to Glyptochiton cordifer (de Koninck, 1 844) from the Carboniferous of Belgium. Also related, per- haps even more closely, are the Scottish Car- boniferous species G. youngianus (Kirkby in Young, 1865), G. kirkbyanus (Etheridge, 1882), and G. quadratus (Etheridge, 1882). symmetricus Trenkner, 1 868 Chiton symmetricus Trenkner, 1868:137, pi. 2, fig. 30. Clarke 1885:338. See: corrugatus Sandberger and Sandberger, 1856. Geological Age. — Devonian. Locality.— Germany: Winterborg, Hartz Mts. Location of Material. — Unknown. Remarks. — Clarke (1885) considers this species to be identical with Probolaeum corru- gatus (Sandberger and Sandberger, 1856), and we agree. texanus Girty, 1909, Cymatochiton! Cymatochiton! texanus Girty, 1909:451, pi. 29, fig. 21, 21a. Branson 1948:761. Cymatochiton! texanus Girty. Yochelson 1971:130, 132. Pterochiton! texanus (Girty). Hoare and Smith 1984:82, fig. 10N-P. Geological Age.— Permian. Locality. — USA: Texas, Delaware Mountain Formation, South Delaware Mts., 48.3 km east of Van Horn, Van Horn Quadrangle. U.S. Geological Survey locality G-2969-PC. Location of Material. — Holotype, USNM-1 18324. Remarks.— The species is based on a single, poorly preserved, intermediate valve collected by G. B. Richardson. It is triangular, rather low- arched, with a blunt jugal ridge and gently convex side-slopes that form an angle of divergence of slightly more than 90°. The posterior margins sweep forward and form an angle of a little less than 90° at the weakly mucronate apex. There is no evidence of insertion plates. The sutural lam- inae are well developed, subtriangular in shape, with a rather narrow sinus between them. On the ventral side the articulamentum has two thick- ened ridges extending from the bases of the su- tural laminae nearly to the valve apex. All traces of dorsal sculpture, if any, have been lost in pres- ervation, the valve showing a coarse crystalline structure resulting from acid etching. Measure- ments are: length (over-all), 6.6 mm; length along the dorsal median line, apex to base of sutural sinus, 5.5 mm; height, 2.5 mm. Assignment of this valve to Cymatochiton Dall, 1882 [type C. loftusianus King, 1848, by original designation] from the Permian of England can be based only on the triangular shape of the in- termediate valve of C. texanus as compared with that of C. loftusianus. Cymatochiton texanus does not seem to be related in any way to other beau- tifully preserved, acid-etched valves from the Permian of West Texas in the collection of the USNM. Thus its systematic position must re- main tentative pending collection and study of additional material from the type locality, es- pecially head and tail valves. The above comments are based on a study of the unique holotype of Cymatochiton texanus [loaned through the courtesy of Dr. Jess Merida of the United States Geological Survey, Wash- ington, D.C.]. tholus (Hoare, Mapes, and Atwater, 1983), Euleptochiton Pterochiton tholus Hoare, Mapes, and Atwater, 1 983:997-999, fig. 2C, 5A-K. Geological Age. — Lower Pennsylvanian (Morrowan). Locality. — USA: Oklahoma, Gene Autry Formation ex- posed in gullies on east side of unnamed tributary of Sycamore Creek on the Daube Ranch, NW'A NW'A SWA, sec. 2, T 4S, R 4E, Johnson Co. Location of Material. — Holotype, OSU-34809; para- types, OSU-348 1 0-348 1 7. Remarks.— A very small species approxi- mately 10 mm long and 3.5 mm wide when re- constructed giving a length to width ratio of 2.9: 1 . The valves are ornamented by very fine pus- tules in a quincunx pattern. The lateral margins of the intermediate valves are narrowly rounded and the tail valve is highly arched with steep slopes. The mucro on the tail valve is located further posteriorly than in Euleptochiton spat- ulatus (Hoare, Sturgeon, and Hoare, 1972). Average dimensions are (mm): Head Intermediate Tail Length Width Height 1.3 2.7 1.2 1.8 3.3 1.4 2.0 2.6 1.3 SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 55 thomondiensis (Baily, 1859), Ptewchiton Chiton thomondiensis Baily, 1859:331-332, pi. 28, fig. 2, 2a- c. Baily 1860:95 (and footnote). Kirkby 1862:237. Roche- brune 1883:4. Ptewchiton thomondiensis (Baily). Dall 1882:281. Sirenko and Starobogatov 1977:36. Anthracochiton thomondiensis (Baily). Rochebrune 1883:27. Geological Age.— Carboniferous. Locality. — Ireland: Carboniferous limestone of Lisbane and Rathkeale, County Limerick. Location of Material. — Specimens in BM (N.H.) (fide H. W. Ball). Remarks. — Chiton thomondiensis is based on four detached intermediate valves with two frag- ments "of what appears to be the under surface of its very thin shell, showing markings for the attachment of muscles . . . ." Two of the valves are beautifully preserved. Baily's measurements (converted from inches to mm) are: Width Length Height Largest 33.0 22.9 Medium 30.2 13.5 Smallest 22.9 17.8 3.2 The enlarged reconstruction of an entire animal (valves only) is upside down on the plate (fig. 2c). Baily's description follows: Shell elongated. Plates subquadrate and very thick, broad- er than long, having a median elevation, or prominent ridge, with an acuminated apex; surface concentrically striated by lines of growth, which become broken into granulations on each side of the central ridge, about ten faint radiating lines proceeding from the apex to the pos- terior margin; apophyses widely separated. Baily's paper describing this species was read at a meeting of the Geological Society of Dublin in June 1859. Since his first collection of "plates belonging to several individuals" he found more later "in a cutting at Rathkeale, on the Limerick and Foynes Railway." He thought his species was related to Chiton gemmatus de Koninck, 1844 [=C. subgemmatus d'Orbigny, 1850] and that it might occupy a position between this and Hel- minthochiton priscus (Minister, 1839). Chiton thomondiensis is the first in the list of Rochebrune's species assigned to Anthracochiton Rochebrune, 1833 and is herein selected as the type species of that genus. The broad, well- developed sutural laminae and excavated an- terolateral margins of this species are evidence for its allocation to the genus Ptewchiton Car- penter in Dall, 1882 of which Anthracochiton is considered to be a synonym. thraivensis (Reed, 1911), Septemchiton? Helminthochiton thraivensis Reed, 1911:337-339, pi. 15, Smith 1960:148, fig. 33,2a-c. Gotlandochiton thraivensis (Reed). Sirenko and Starobogatov 1977:31. Septemchitonl thraivensis Rolfe, 1981:677. Geological Age. — Middle Ordovician (Upper Bala). Locality.— Scotland: Thraive Glen, Girvan, from the Star- fish Beds (Upper Bala). Location of Material. — Holotype, along with other ex- amples, in BM (N.H.) (fide H. W. Ball). Remarks.— Reed's illustrations are good; one showing a complete specimen with girdle spic- ules is well preserved. According to Reed, other specimens show valve pores in both cast and mold; he says there are several more or less per- fect specimens in Gray's collection. The single specimen with preserved girdle spicules is only one of two species that throws any light whatever on the girdle characters of Paleozoic polyplacophorans, the other being Glaphurochiton concinnus (Richardson, 1956). It would be assuming too much to infer that the typical Paleozoic polyplacophoran had a spicu- lose girdle although such an assumption might be a reasonable one in view of the fact that many Recent species in the family Lepidopleuridae have a spiculose girdle decoration. tornacicola de Ryckholt, 1845. Genus incertae sedis Chiton tornacicola de Ryckholt, 1845:45-46, pi. 1, fig. 1-3. Salter 1847:50, 52. Bronn 1848:292. Kirkby 1862:237. de Koninck 1883:211. Rochebrune 1883:32. Jaekel 1900:13. ICymatochiton tornaticola [sic] Dall, 1882:282. Geological Age. — Lower Carboniferous. Locality. — Belgium: Tournai, ". . . dans l'argile de Tour- nay, subordinee au systeme anthraxifere superieur . . ." (de Ryckholt). Location of Material. — Unknown. Remarks.— This species is based on two ex- tremely small specimens, 4 mm in length. De Koninck (1883), thought one represented a species of cephalopod. Dall (1882) thought it had "some crustacean features" and Rochebrune referred it to the crustacean Philipsia. The identification of Chiton tornacicola as a polyplacophoran is here rejected. 56 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 torus Hoare and Mapes, 1985a, Euleptochiton Euleptochiton torus Hoare and Mapes, 1985a:875-877, fig. 1. Geological Age. — Upper Pennsylvanian (Virgilian). Locality.— USA: Texas, Finis Shale exposed in gullies south of dam, 0.4 km east of Hwy. 59 and 8.3 km NE of Jacksboro, Jack Co., Cundiff 7'/2-minute Quadrangle. Location of Material. — Holotype, OSU-36982; para- types, OSU-36983-36991; BGSU-4446. Remarks. — Reconstructed specimens are small, about 20 mm long, and have broad sutural laminae. The intermediate and tail valves show slight divisions into lateral, central, and posterior areas. The intermediate valves bear a distinct narrow jugal ridge that projects as a jugum into the jugal sinus. The tail valves are semicircular with the mucro located anterior to midlength. The head valve is unknown. Average dimensions are (mm): Intermediate Tail Length Width Height 4.0 6.5 2.8 3.0 4.9 1.6 This genus and species was mistakenly as- signed originally to the family Ochmazochiton- idae Hoare and Smith, 1 984 by Hoare and Mapes (1985a). It is here placed in the Permochitonidae Sirenko and Starobogatov, 1977. trapezoidalis Trenkner, 1868, "Chiton" Chiton trapezoidalis Trenkner, 1868:137-138, pi. 2, fig. 32. Clarke 1885:338-339. Quenstedt 1931:553. Geological Age.— Upper Devonian (Ibergerkalk). Locality.— Germany: Winterborg, Hartz Mts. Location of Material. — Unknown. Remarks.— The species is based on an inter- mediate valve 13 mm long and 23 mm wide. Clarke (1885) placed Chiton [=Probolaeum] cor- rugatus Sandberger and Sandberger, 1 856 in syn- onymy with "C." trapezoidalis, which is incor- rect as the Sandberger species is the older. triangulatum Carpenter in Dall, 1882, Gryphochiton Gryphochiton triangulatum Carpenter in Dall, 1882:280. Geological Age. — Lower Carboniferous. Locality.— Belgium: Tournai. Location of Material. — Specimens provisionally identi- fied as this species by P. P. Carpenter, MCZ (Schultze Collec- tion). Remarks.— This species name is based on Carpenter's manuscript and, according to Dall, applies only to specimens illustrated by de Ryck- holt (1845) in his plate 2, figures 4, 9-10. Ac- tually, figure 4 is listed as Chiton turnacianus: figures 9-10 as C. mempiscus. Apparently he thought these illustrations represented a different species. The Schultze Collection in the MCZ contains a specimen from Tournai (part of Lot No. 1 6370), with a note in Carpenter's handwriting as fol- lows: "Probably part of side valve of Gryphochi- ton triangularis (but may be another species, al- lied to Rhyckholtianus). If this is triangulatus a good deal has been lost behind." This specimen consists only of the left half of an intermediate valve with indications of a rather short sutural lamina. The upper surface is irregularly and deeply grooved concentrically, with a suggestion of some scattered, rounded granules. It seems to belong to the genus Gryphochiton, the species indeterminate. Another specimen (from Lot No. 16379) has the following Carpenter comment: "16379 Chiton priscus (pars) teste Koninck. Carb. Tournay =Gryphochiton triangulatus. (Probably part of posterior valve] but may be centr. valve)." While too fragmentary to identify with any cer- tainty, it has the swept-wing appearance on which Carpenter's name was based. (For a similar swept- wing chiton, see Smith (1960), p. 153, fig. 36,6b- d.) Gryphochiton triangulatum, therefore must rest its identity on only the slim evidence of old il- lustrations. It can be validated only if de Ryck- holt's actual specimens can be found and studied with reference to other named species from Bel- gium. troedssoni Bergenhayn, 1955, Gotlandochiton Gotlandochiton troedssoni Bergenhayn, 1955:19-20, pi. 1, fig. 9 (type); pi. 2, fig. 7 (reconstruction). Smith 1960:150, fig. 34,7 (type) [ex Bergenhayn]. Van Belle 1975a, pi. 1, fig. 7. Sirenko and Starobogatov 1977:31. Geological Age.— Silurian (Gotlandian). Locality.— Sweden: Gotland. Landspitze von Grotlingbo and Gansviken, Grotlingbo. Location of Material. — Type, RM Mo-6032; syntype?(or paratype), RM Mo-6036. Remarks.— The species is based on half of an intermediate valve and two other intermediate valves. Bergenhayn's illustration of the type SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 57 specimen lacks detail and indicates a much-worn The allocation to the genus Gryphochiton Gray and possibly a poorly-preserved valve. (1847a) seems proper for these species. tumidus de Koninck, 1857, "Chiton" Chiton sp. Roemer, 1855:36, pi. 7, fig. 9a-b. Chiton tumidus de Koninck, 1 857: 196 (new name). Baily 1859: 333; 1860:95. Rochebrune 1883:24. Geological Age. — Upper Devonian. Locality.— Germany: Grund, Hartz Mts. Location of Material. — Unknown. Remarks. — According to Rochebrune, de Koninck named this species from an undesig- nated illustration published by Roemer. He doubted that it was a polyplacophoran, believing it to be a brachiopod (Spirifer) or possibly a lim- pet (Leptena). Roemer's (1855) illustrations ap- pear to represent a head valve of a polyplacoph- oran. turnacianus (de Ryckholt, 1845), Gryphochiton Chiton turnacianus de Ryckholt, 1845:54-55, 62, pi. 2, fig. 1- 4. Bronn 1848:292. de Koninck 1857:196. Baily 1859:333; 1860:95. Kirkby 1862:237. Bigsby 1878:318. Gryphochiton turnacianus (de Ryckholt). Rochebrune 1883: 25, 26. Sirenko and Starobogatov 1977:35. Helminthochiton turnacianus (de Ryckholt). Salter 1847:52. de Koninck 1883:201, pi. 50, fig. 32; pi. 51, fig. 1-2, 15-18, 23, 24. Geological Age. — Lower Carboniferous. Locality. — Belgium: Tournai. From "l'argile subordinee ou systeme anthraxifere superieur de Tournay" (de Ryckholt). Location of Material. — PSM (Rochebrune), but P.-H. Fischer does not list it from this collection. BM (N.H.) (fide H. W. Ball). Remarks. — De Ryckholt illustrated an inter- mediate and a tail valve. The side view of the latter shows small sutural laminae but the view of the intermediate valve does not. In the Schultze Collection in the MCZ there are three large in- termediate valves (Lot. No. 16370) from Tour- nai accompanied by the following note by P. P. Carpenter: "16,370 Chiton priscus (pars) De- Koninck Carb. Tournay. ^Gryphochiton mem- piscus DeRyckholt {=turnacianus DeKon. in Va. [= Vienna?] Mus." Rochebrune (1883) thought Helminthochiton turnacianus and H. priscus (Miinster, 1839) were conspecific. The validity oVChiton" turnacianus, and "C." mempiscus de Ryckholt, 1 845, as well, both need more specific proof than is presently available that either or both are separable from priscus. variabilis Walcott, 1885, Matthevia Matthevia variabilis Walcott, 1885:17, pi. 20, fig. 1-6 [type species of Matthevia Walcott, 1 885, by original designation]. Walcott 1886:223-225, pi. 32, fig. 1-12; pi. 33, fig. 1, la-f. Miller 1889:392, fig. 647. Lesley 1889:381-382 (text-fig. ex Walcott 1886). Walcott 1912:265, pi. 41. Fisher 1962:128, text-fig. 72, la-g. Yochelson 1966:B1-B1 1, text-fig. 1-2, 3A- C, pi. 1. Runnegar, Pojeta, Taylor, and Collins 1979:1390, pi. 1, fig. 5-30, text-fig. 1. Geological Age. — Upper Cambrian, correlative of the low- er part of the Trempealeau, the youngest of the three stages of the Upper Cambrian. Localities. — USA: New York, near Saratoga Springs, Hoyt Limestone Member, Theresa Dolomite (Walcott). Texas, Wil- berns Formation (Cloud and Barnes). Utah, Desert Valley, Ajax Formation (Reso). Nevada, Nopah Formation. Okla- homa, Arbuckle Mts. (Josiah Bridge, fide W. Ham). For details, see Yochelson, McAllister, and Reso. ?Alberta (Yochelson and Taylor). Wisconsin, near Baraboo, Black Earth Member, St. Lawrence Formation (Runnegar, Pojeta, Taylor, and Collins). Location of Material. — Lectotype, USNM- 1 46894; para- lectotypes, USNM-258992-259002, plus other specimens. Remarks.— Yochelson (1 966) has proposed the establishment of a new class in the Mollusca, Mattheva, for M. variabilis, placing it in the fam- ily Matthevidae Walcott, 1885, genus Matthevia. He provides a thorough description and discus- sion along with excellent illustrations. The lan- ceolate shape of many of the Matthevia fossils is somewhat similar to that described as Calceo- chiton hachitae Flower, 1968, from the Early Or- dovician of New Mexico, and also Calceochiton cf. gibberosum (Sardeson, 1 896), neither of which, however, exhibit the ventral pocket in many of the valves of Matthevia. Polyplacophoran valves that do have a ventral pocket, from the Early Carboniferous of Scotland and the Permian of West Texas, are quite small in size and consid- ered to be tail valves (intermediate valves are normal in shape with no ventral pocket); they are placed in a proposed new genus, Soleachiton (Hoare and Smith 1984:90). Yochelson interpreted Matthevia fossils to consist of head and tail valves only. Thus he made no attempt to equate them with the Poly- placophora although he does not rule out the possibility that intermediate valves might exist. Smith studied these fossils with Yochelson sev- eral years ago and was in agreement with this view. He felt the attempt to pick out specimens that might be called intermediate valves was 58 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 tempting, but they were unable to do this with any assurance at that time. Runnegar and Pojeta (1974), and later Run- negar et al. (1979), took the step of classifying Matthevia in the Polyplacophora, evidently bas- ing this decision on a study of valves of a species of chelodid polyplacophoran from the Early Or- dovician of Australia. Under this hypothesis, Matthevia from the Cambrian represents prim- itive stock from which an Early Ordovician che- lodid developed (as represented by the Austra- lian fossil), followed by a later development of the genus Chelodes in the Lower Paleozoic. Un- der this hypothesis, the evolutionary trend begins with rather pointed, lanceolate valves growing in an erect position in life and continues with a gradual flattening, widening, and possibly a thickening of the valves more or less similar to the supposed somewhat flattened but extensively overlapping valves of Chelodes. Also assumed is the fact that the 8-valved condition of the Poly- placophora may have been a primitive devel- opment. variegatus Bergenhayn, 1955, Chelodes Chelodes variegatus Bergenhayn, 1955:13-14, pi. 1, fig. 4 (type); pi. 2, fig. 3 (reconstruction). Sirenko and Starobogatov 1977: 31. Geological Age. — Silurian (Gotlandian). Locality. — Sweden: Gotland, Grotlingbo, Gansviken, and Atlingbo. Location of Material. —Type, RM Mo-60 1 1 ; syntype? (or paratype). RM Mo-6005. Remarks.— The species is based on two in- termediate valves. Bergenhayn illustrated only the side view of his type specimen. vermiformis Bergenhayn, 1955 Septemchiton vermiformis Bergenhayn, 1955:24-26, pi. 1, fig. 15 (type); pi. 2, fig. 13 (reconstruction), 13a-b. Smith 1960: 150, fig. 35,la-f(ex Bergenhayn). Rolfe 1981:675-678, text- fig. 1-3. See: grayiae Woodward, 1885. Geological Age. — Middle Ordovician (Upper Bala). Locality.— South Scotland: from the Starfish bed. Location of Material. — BM (N.H.) G-47222, a complete specimen with all valves in place in the matrix. Remarks.— Bergenhayn's name is a subjective junior synonym of Septemchiton grayiae (Wood- ward, 1885). viseticola (de Ryckholt, 1845), Gryphochiton Chiton viseticola de Ryckholt, 1845:51, 62, pi. 3, fig. 10-11. Bronn 1 848:292. deKoninck 1857:195. Baily 1859:333; 1860: 95. Kirkby 1862:237. Bigsby 1878:319. Rochebrune 1883: 32. Gryphochiton (Chonechiton) viseticola (de Ryckholt). Dall 1882: 281. Chonechiton viseticola (de Ryckholt). Tryon 1883:339, pi. 85, fig. 59. Helminthochiton viseticola (de Ryckholt). Salter 1847:52. de Koninck 1883:205, pi. 51, fig. 37-40; pi. 53, fig. 12-20. Gryphochiton viseticola (de Ryckholt). Sirenko and Starobo- gatov 1977:35. Geological Age. — Lower Carboniferous. Locality. — Belgium: Vise, from the . . . "anthraxifere su- p6rieur ..." (de Ryckholt). Location of Material. — MCZ (Schultze Collection). Remarks.— This may be a valid polyplacoph- oran species although de Ryckholt's illustration of the single valve in matrix does not show any sutural laminae. In the Schultze Collection in the MCZ there are five specimens and several frag- ments with an original label carrying this species name. P. P. Carpenter's handwritten note ac- companying the fragments indicated he agreed with the identification. Although preservation is poor for the most part, one of the larger valves and one smaller one have a microsculpture of extremely fine, closely-spaced granules seen only under a magnification of x 10 or higher. Another small valve represents a beaked polyplacophoran but is incomplete and has no particular distin- guishing characters. Both de Koninck and Baily consider that Chi- ton viseticola may be conspecific with C. gem- matus [=C. subgemmatus d'Orbigny, 1850] or a subspecies of it. Rochebrune said it was hard to believe it was a polyplacophoran at all. Dall, on the other hand, made C viseticola the type of the subgenus Chonechiton Carpenter (1882) of the genus Gryphochiton Gray, 1847a. If Dall is correct, the species should be allocated to the genus Gryphochiton. walcotti, Runnegar, Pojeta, Taylor, and Collins, 1979, Matthevia Matthevia walcotti Runnegar, Pojeta, Taylor, and Collins, 1979: 1390-1391, pi. l.fig. 1-3. Geological Age. — Upper Cambrian (Trempealeauan). Localities. — USA: Black Earth Member, St. Lawrence For- mation, Eikey quarry, 9 km east of Baraboo, Wisconsin (USGS locality 217, old series) and 2 km west of Black Earth, Wis- consin (USGS locality 4 1 8 A, old series). Also at Reservoir Hill SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 59 (Bed 21), Mazomanie, Wisconsin (USGS locality 434X1, old series). Location of Material. -Holotype, USNM-258989; fig- ured paratype, USNM-258990. Remarks.— Described from four body valves which are tall, conical, and probably tapered to a sharp apex. The anterior and posterior margins are deeply embayed and have only one hole ven- trally on the posterior side thus differing from Matthevia variabilis Walcott, 1885. whitehousei Runnegar, Pojeta, Taylor, and Collins, 1979, Chelodes Chelodes sp. Runnegar and Pojeta, 1974:312, fig. 3M-0, 5 (middle drawing, reconstruction). Chelodes whitehousei Runnegar, Pojeta, Taylor, and Collins, 1979:1388-1389, pi. 2, fig. 1-59. Stait and Burrett 1984: 112, fig. 1. Geological Age. — Lower Ordovician (lower Tremado- cian). Locality.— Australia. Ninmaroo Formation, Mt. Datson, 50 km east-northeast of Boulia, Queensland; QM locality L 278/G25, Glenormiston Station road about 5 km east of No. 21 Bore; QM locality L 278/G24, Glenormiston Station road about 8 km east of No. 2 1 Bore. Location of Material. — Holotype (UQ F30894) and fig- ured paratypes (UQ F30769A-H, 30959, 30873, 30766), Uni- versity of Queensland and figured paratypes (QM F10087- 10104), Queensland Museum. Remarks. — Head valves unknown. Body valves are narrowly elongate with deep depres- sions ventrally and embayed anterior margins. The tail valves are rectangular to triangular in dorsal view, deeply concave ventrally with a small tapering hole beneath the apex, embayed ante- rior margin and apex located posteriorly. Run- negar and Pojeta (1974) said it is: "intermediate in form between Chelodes and the enigmatic Late Cambrian fossil Matthevia Walcott" which they believe to be a polyplacophoran. Runnegar et al. (1979) believe that more than one species may be included here. woodmillensis Dunlop, 1915, "Chiton''' Chiton woodmillensis Dunlop, 1915:169, pi. 22, fig. 5. Geological Age. — Lower Carboniferous. Locality.— Scotland: Fife; about 1.6 km southeast of Dum- fernline Lower Railway, on the Lyne Burn, and at the bend of the burn below Woodmill Beachfield in strata containing fossils that rest on the Hurlet Limestone. Location of Material. — Specimens from Fife, Scotland, in BM (N.H.) (fide H. W. Ball). Remarks. — In discussing the fossil polypla- cophorans found at Fife, Dunlop said: "I can find nothing figured to compare with Fig. 5: the spec- imen has a cornice around it that none of the others has, and I name it provisionally Chiton woodmillensis" This meager description and the poor illustration of the specimen referred to com- bine to make any further identification impos- sible without careful study and comparison with other described species. Other species cited by Dunlop from the same area are Chiton gem- matus [=C. subgemmatus d'Orbigny, 1850], C. armstrongianus, and C. cordatus. Later, in 1922, Dunlop discussed the fossil polyplacophorans of Woodmill further and raised the question whether they are not all one species. He said: "In the first place, they all seem to have been living in a little carboniferous pool about 10 or 12 feet broad, but of unknown length, as I have worked only about 2 feet. Out of this pool I have received over eighty specimens of Gem- matus, fourteen of Armstrongianus and twelve of Cordatus. These sometimes have been found together, and their relative numbers suggest that they represent but one species of Chiton. All three species also present the same microscopic struc- ture . . . ." wright ian us de Koninck, 1857. Genus incertae sedis Chiton wrightianus de Koninck, 1857:196, 199, pi. 1, fig. 2a- c. Baily 1859:333; 1860:96, 97, pi. 2, fig. 2a-c. de Koninck 1860:97, pi. 2, fig. 2a-c. Woodward 1865:489, pi. 14, fig. la-1. Dall 1882:283. Rochebrune 1883:20. Quenstedt 1882: 682. Withers 1926:37-42, pi. 5, fig. 1-6; pi. 6, fig. 1-8. Geological Age.— Silurian (Wenlock). Locality. — England: near Dudley. Location of Material.— Holotype, BM (N.H.) 1-16283 plus two additional specimens (fide Withers). Original Description. — "The form of the dorsal plates of this species is subtriangular, the posterior edges making very nearly a right angle. The lateral areas are rounded, and the anterior edge is very sinuous. All the plates are supplied with a well marked median carina, and appear to be without apoph- yses. The surface is covered with a small number of deep equidistant striae. The test is slender. The median area is larger than the lateral one. Dimensions.— The length of each dorsal plate is about 8 millimeters, and the breadth 12 mm" (de Koninck 1857:199). Remarks. — De Koninck's illustrations are stylized drawings. Figure 2a shows a matrix with two adjacent valves having partial coverage. Fig- ure 2b is an edge view of a valve from the pos- terior end. Figure 2c shows a reconstruction with all eight valves "taking as a base Chiton loftu- 60 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 sianus." No mention is made of end valves. Woodward (1865) thought C. wrightianus was a cirripede of the genus Turrilepas, a view with which Rochebrune (1883) agreed and which Withers (1926) confirmed. yochelsoni, Hoare and Smith, 1984, Soleachiton Soleachiton yochelsoni Hoare and Smith, 1984:90-92, fig. 4 (reconstruction), 5A-V [type species of Soleachiton Hoare and Smith, 1984, by original designation]. Geological Age. — Lower and Middle Permian (Wolfcam- pian, Leonardian). Localities. — USA: Texas, Leonard Formation, USNM loc. 702; Road Canyon Formation, USNM loc. 703a; Cathedral Mountain Formation, USNM Iocs. 703a', 703bs; Bone Spring Formation, USNM loc. 725d, Glass Mts., West Texas. Location of Material. — Holotype, USNM-330848; para- types, USNM-330849-330862. Remarks.— A reconstructed specimen mea- sures approximately 23 mm in length and 10 mm in width with a length to width ratio of 2.3:1. The head valve is known from only a fragmen- tary specimen. The intermediate valves are high- arched (jugal angle averaging 103°), swept-wing, and mucronate with the apical angle averaging 98°. The side-slopes are slightly convex with no differentiation of lateral and central areas. The sutural laminae are small, short, and rounded. The tail valves are triangular in plan view, high- arched, with a terminal mucro overhanging the posterior margin. Fine ridges radiate from the mucro on some specimens. Ventrally, the pos- terior portion is a hypotyche forming a posterior pocket and the sutural laminae are broad, short, and rounded. No definite ornamentation or sculpture is present, the valve surfaces being smooth. Average dimensions are (mm): Intermediate Tail Length Width Height 4.4 5.9 3.0 4.7 4.7 2.8 The new genus Soleachiton Hoare and Smith, 1984 was erected to contain those species with triangular tail valves having a terminal mucro, and possessing a hypotyche on the ventral sur- face of the valve. The family Acutichitonidae Hoare, Mapes, and Atwater, 1983, containing the genus Acutichiton Hoare, Sturgeon, and Hoare, 1972 and Arcochiton Hoare and Stur- geon, 1976, would appear to be the logical fa- milial assignment for Soleachiton. youngianus (Kirkby in Young, 1865), Glyptochiton Chitonellus youngianus Kirkby in Young, 1865:14-15, pi. fig. 2. Kirkby and Young 1867:341-342, pi. 16, fig. 2-4. Young 1878:324. Etheridge 1882:101-102, pi. 2, fig. 23-24. Chiton youngianus (Kirkby in Young). Rochebrune 1883:33- 34 (see "yungianus"). Glyptochiton youngianus (Kirkby in Young). Smith 1960:172, fig. 44,6a-b (ex Etheridge). Smith 1971:567, 572. Sirenko and Starobogatov 1977:37. Geological Age. — Lower Carboniferous (Main or Hurlet Limestone). Localities. — Western Scotland: Craigenglen, Campsie, Ayr- shire, in marine shale (Kirkby); Cunningham Baidland, near Dairy (Etheridge). Location of Material.— Collection of J. Armstrong (fide Etheridge). Present location unknown. Remarks.— The species is based on a single tail valve and two probable intermediate valves. The illustrations show an oval or ovate tegmen- tum, beaded circularly, with an elongate-ovate, smooth center. The articulamentum is exten- sively developed anteriorly, with a fairly deep sinus. Dimensions of one of the intermediate valves is given as: length, 9/32 in. (7 mm); breadth, %2 in. (3.2 mm). Kirkby's description seems quite complete as it covers all significant details. Kirkby and Young (1867) reported the collec- tion of portions of two intermediate valves, which they described and illustrated. A third valve col- lected was lost. Etheridge (1882) described and illustrated a well-preserved tail valve that seemed to him to exhibit characters of both Chitonellus subquad- ratus Kirkby and Young, 1867 and C. youngi- anus. He indicated that possibly the two species were conspecific, and also called attention to the fact that one of de Ryckholt's illustrations of C. cordifer (1845, pi. 4, fig. 10) was much like the tail valve of C. youngianus. This species has been assigned subsequently to the genus Glyptochiton de Koninck, 1883 with G. cordifer (de Koninck, 1844) as type; other related species include G. subquadratus and G. kirkbyanus (Etheridge, 1882). Recorded but Unnamed Paleozoic Species The following citations are included in order to have a record of miscellaneous undetermined SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 61 polyplacophoran valves that have been noted in the literature, or that have been brought to the attention of the writers. It is hoped that a listing of the localities will result in additional collecting and thus produce valuable material for future study. Genus and species indeterminate Smith in Smith and Toomey, 1964:31, pi. 8, fig. 1-3. Geological Age. — Lower Ordovician (Kindblade Forma- tion). Locality.— USA: Oklahoma. Arbuckle Mts. (See Gotlan- dochiton hami Smith in Smith and Toomey, 1 964). Location of Material.— OU-5231. Remarks.— A single, poorly-preserved inter- mediate valve, referable with some doubt only to the family Gotlandochitonidae. "Chiton" sp. de Koninck, 1857:196. Baily 1859: 333; 1860:95. Geological Age. — Middle Devonian. Locality. — England: Plymouth. Location of Material. — Said to be based on material in the Geological Survey Collection, London. "Chiton" sp. nov. Kirkby, 1862:236. Geological Age.— Carboniferous (Lower Scar). Locality. — England: Settle, Yorkshire, near the base of the Lower Scar subdivision of the Mountain Limestone. Location of Material. — Unknown. Remarks. — Found along with Chiton burrow- ianus Kirkby, 1862, C. coloratus Kirkby, 1862, and valves of a couple of other species not named by Kirkby at the time. Kirkby said: "Besides the preceding plates, there is a cast of a patelliform shell among Mr. Burrow's specimens that may be a plate of a Chiton or Chitonellus. It is % inch [19 mm] long, rather convex, and slightly flanged marginally; and a posterior plate of an undoubt- ed Chiton rests upon one side of it. I do not describe it with the other plates, because I cannot detect traces of apophyses, nor satisfy myself as to its shell-structure, nor yet perceive anything conclusive of its relation to this family" (1862: 236). "Chiton" sp. Richter, 1863. Geological Age. — Middle Devonian. Locality.— Germany. Location of Material. — Unknown. Remarks. — Based on a reference by Roche- brune (1883:23-24). According to Rochebrune, Richter cited a polyplacophoran in a long list of Devonian fossils from the pflanzen Sandstein but did not describe or illustrate it. He said it was the same as another unnamed polyplacophoran from the Devonian of Plymouth, England, to which a vague reference was made by Bigsby (1878:319) and also in the 4th volume of the Memoirs of the Geological Survey. The reference to the Richter paper to which Rochebrune refers was not located. "Chiton" sp. Etheridge, 1882:91-92, pi. 1, fig. 16-17. Geological Age. — Lower Carboniferous. Locality.— Scotland: Gallowhill, near Strathaven, Lanark- shire. Location of Material.— Collection of J. Thompson (fide Etheridge). Present location unknown. Remarks.— The specimen is a single, moder- ately large intermediate valve. No dimensions are given. Etheridge compared it with Chiton gemmatus de Koninck, 1842:323, pi. 23, fig. 2c [=C. subgemmatus d'Orbigny, 1850:127] and points out several important differences, one being the much narrower and stronger sutural laminae, which "project more from the front." "Chiton" sp. indet. Etheridge, 1882:92, pi. 2, fig. 10. Geological Age. — Lower Carboniferous (Main or Hurlet Limestone). Locality. — Scotland: near Dairy, Ayrshire, from the Law Quarry. Location of Material. — Collection of J. Armstrong (fide Etheridge). Present location unknown. Remarks.— Based on a fragment of what Eth- eridge thought might be an intermediate valve, which has a single most peculiar spike or tooth- like apophysis. This certainly is not like the su- tural lamina on any fossil polyplacophoran and its identification as a polyplacophoran rests on extremely doubtful grounds. "Chiton" sp. indet. Etheridge, 1882:95, pi. 1, fig. 23-24. Geological Age. — Lower Carboniferous (Main or Hurlet Limestone). Locality. — Scotland: near Dairy, Ayrshire, from the Law Quarry. Location of Material.— Collection of J. Smith (fide Eth- eridge). Present location unknown. Remarks. — Based on one or two valves that 62 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 are said to be different from those of other British Carboniferous species. Etheridge said the head valve comes closest to his Chiton geikiei without the marginal projections characteristic of this species. The dorsal sculpture consists of micro- scopic granulations. The sutural laminae are small and rather pointed. The material is too meager for more than a casual reference to fossil valves that subsequently may be determined as coming within the range of variation of an already described species. 4E), Mill Creek section, in a zone of abundant Calathium, 37.2 m above the base of the Kindblade Formation. Location of Material. — OU-5222. Remarks.— A single intermediate valve, al- most square, measures 7.8 mm long, 7.9 mm wide, and 3.0 mm high, with a jugal thickness of 1.5 mm. The angle of divergence of the side- slopes is about 120°. This has some aspects of Ivoechiton oklahomensis Smith, 1964 but differs from all other valves found in the Mill Creek section. "Chiton" sp. Reed, 1907:114, pi. 4, fig. 13-14. Geological Age. — Silurian (Upper Bala). Locality. — Scotland: Girvan area, Penwhipple and Thraive glens. Location of Material.-BM (N.H.) (fide H. W. Ball). Remarks. —The illustrations look like an elon- gate intermediate valve of a species of Chelodes. Chelodes"} sp. indet. Bergenhayn, 1960:175, fig. 17-18. Geological Age.— Lower Ordovician. Locality.— USA: Missouri. Location of Material. — USNM-137378. Remarks. — Based on a tail valve and an impression of another tail valve, too poorly pre- served for identification to species. Found with Chelodes depressus Bergenhayn, 1960. Priscochitoril sp. indet. Bergenhayn, 1960:175, fig. 19-20. Geological Age. — Upper Cambrian (lower "Ozarkian"). Locality. — USA: New York, on south side of a hill north of Mrs. Josie A. Hall's house, Whitehall, Washington County. Location of Material. — USNM- 137377. Remarks. — Based on a supposed tail valve 7 mm long and 4 mm wide, with the lateral slopes weakly concave, forming a jugal angle of 120°. The mucro is far back, the posterior part of the valve weakly concave. This is certainly not ap- plicable to the genus Priscochiton as represented by P. canadensis (Billings, 1865), and its assign- ment as a polyplacophoran is doubtful. Ivoechiton sp. Smith in Smith and Toomey, 1 964: 23, pi. 4, fig. 16-18. Geological Age. — Lower Ordovician (Kindblade Forma- tion). Locality.— USA: Oklahoma, Murray County, 9.7 km west- southwest of Mill Creek village (SWA SW'A, sec. 17, T 2S, R Kindbladochiton sp. Smith in Smith and Toomey, 1964:27-28, pi. 6, fig. 10-12. Geological Age. — Lower Ordovician (Kindblade Forma- tion). Locality. — USA: Oklahoma, Murray County, 9.7 km north of Woodford, on the original Joins Ranch (SE'A NW'A NE'A, sec. 4, T 2S, R 1 W), Joins Ranch section, in a zone of abundant Calathium, 460-500 feet above the base of the Kindblade Formation. Location of Material. — OU-52 18. Remarks.— Based on a single specimen con- sisting of two separate valves fused into one, more likely the result of injury while living and less likely due to an artifact of fossilization. Found with Kindbladochiton arbucklensis (Smith, 1964), to which it appears to be related. Gotlandochiton sp. Smith in Smith and Toomey, 1964:30-31, pi. 17, fig. 16-18. Geological Age. — Lower Ordovician (Kindblade Forma- tion). Locality. — USA: Oklahoma, Murray County, 9.7 km west- southwest of Mill Creek village (SW'A SE'A, sec. 17, T 2S, R 4E), Mill Creek section, in a zone of abundant Calathium, 37.2 m above the base of the Kindblade Formation. Location of Material.— OU-5228. Remarks.— A single intermediate valve, 5.5 mm long, 10.8 mm wide, and 4.2 mm high, with a maximum jugal thickness of 1.1 mm, and an angle of divergence of the side-slopes of about 108°. It is related to Gotlandochiton hami Smith, 1964, but more specimens like it are needed to establish its species identity. Family Lepidopleuridae, no genus or species in- dicated. Batten 1972:10, fig. 1-2. Geological Age. — Permian. Locality.— Lee Mine No. 8, Kampar, Perak, Malaysia, Misellina claudiae Zone. Location of Material. — American Museum of Natural History, New York, AMNH-29023-29024. SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 63 Remarks.— Available material consists of six valves (three well-preserved and three poorly preserved) of which two are intermediate valves and four are end valves. Figure 1 is of a well- preserved tail valve with a central mucro and a rather fine, closely spaced granular sculpture. Possibly it can be referred to the genus Ptero- chiton, s.l. Figure 2 represents an end valve front view, showing no especially definitive shape or sculpture. "Chiton?" sp. Weller, 1903:173-174, pi. 13, fig. 1-10. Geological Age. — Middle Ordovician (Trenton Lime- stone). Locality. — USA: Jacksonburg, New Jersey. Locality of Material. — Holotype in New Jersey Geolog- ical Survey Collection (Paleontology). Plastotype in Walker Museum Collection, University of Chicago, New Jersey Col- lection, Paleontology Collection No. 10239 [now in Field Mu- seum of Natural History, Chicago]. Remarks.— Weller's description follows: A single plate, probably the posterior terminal one, has been observed in the New Jersey collections, which prob- ably belongs to one of the Chitons. Its true generic ref- erence is uncertain, but doubtless it is not a member of the recent genus Chiton. It is subpentagonal in outline, obtusely angular in front, its posterior margin slightly sin- uate. Along the median line it is quite sharply rounded toward the apex, but becomes more broadly rounded pos- teriorly, with a slight, longitudinal, median groove, be- coming stronger posteriorly. The sides slope down to the lateral margins with a gentle convexity. The surface is smooth. Its dimensions are: length, 7 mm; breadth, 7 mm. The plastotype of the holotype, at present in the Field Museum of Natural History, Chicago, was loaned for study through the courtesy of Ger- ald Forney, Department of the Geophysical Sci- ences, University of Chicago. Although stated by Weller to be a tail valve, it more likely represents an intermediate valve slightly longer than wide (7.3 mm long compared with the 7.0 given by Weller). The aspect is swept-wing, with the pos- terior margins angled forward approximately 70° from the valve apex. The anterior margin is in- dented by a shallow sinus. The valve is gently round-backed, with an indication of a subob- solete jugal ridge; otherwise there is no evidence of a separation into lateral or lateropleural areas. Also, there is no evidence of the presence of su- tural laminae. The ventral side is not exposed. This fossil polyplacophoran cannot be allo- cated to a family on the basis of an investigation of the plastotype. Study of the holotype specimen is necessary before any judgment can be made regarding its systematic position. Genus and species unknown. Cloud and Barnes 1946:282, 365. Geological Age. — Lower Ordovician. Locality. — USA: Texas, El Paso and Tomyard formations, Ellenberger Group. Moore Hollow section and Franklin Mts. section (Cloud and Barnes). Location of Material. — Unknown. Remarks. — Mentions presence of polypla- cophoran plates in the Ellenberger Group. No description or illustrations given. "Chiton" sp. Mendes, 1952:302. Geological Age. — Permian. Locality. — Brazil. Locality unknown. Location of Material. — Unknown. Remarks.— One valve of a polyplacophoran reported. No description or illustrations. Unknown genus and species, Plas, 1972:252-253. Geological Age. — Lower Permian (Bird Spring Group). Locality. — USA: Nevada. Arrow Canyon Range, Arrow Canyon Quadrangle, southeastern Nevada. Location of Material. — Unknown. Remarks. — More than 40 valves of a new ge- nus and species of polyplacophoran extracted from limestone of Unit I by acidization. Not figured or described. Tail valve is concave in lateral outline. Helminthochiton sp. Plas, 1972:252-253. Geological Age. — Lower Permian (Bird Spring Group). Locality. — USA: Nevada. Arrow Canyon Range, Arrow Canyon Quadrangle, southeastern Nevada. Location of Material.— Unknown. Remarks.— Three or four valves of what is probably a Gryphochiton extracted from lime- stone of Unit I by acidization. Not figured or described. Pterochiton sp. A, Hoare and Sturgeon, 1979: 179, pi. 2, fig. 10-11. Geological Age.— Upper Pennsylvanian (Missourian). Locality. — USA: Ohio. Brush Creek Shale at road-cut ex- posure on Ohio Rte. 13, 1.3 km north of Glocester, Athens Co., Ohio. Location of Material. — Hypotype, OSU-30353. Remarks.— One small, incomplete, tail valve 64 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 which appears close to Glaphurochiton carbo- narius (Stevens, 1858) but has a finer surface ornamentation of granules. Additional material is needed to make a valid comparison with G. carbonarius. Indeterminate lepidopleurid genus and species A, Hoare and Smith, 1984:100-101, fig. 9K-N. Geological Age.— Middle Permian (Leonardian). Locality.— USA: Texas, Road Canyon Formation, USNM loc. 703c, Glass Mts., West Texas. Location of Material. — Hypotype, USNM-330894. Remarks.— One nearly complete intermediate valve. Valve highly arched, twice as wide as long, with straight side-slopes which are not divided into lateral and central areas. The sutural lami- nae are short and broad. The jugal angle mea- sures 86° and the apical angle 1 10°. The surface is ornamented with fine ridges radiating from the mucronate apex and on the side-slopes the closely spaced ridges are sinuous, running horizontally. The valve measures (mm): length, 4.5; width, 9.5; height, 5.6. Indeterminate lepidopleurid genus and species B, Hoare and Smith, 1984:101, fig. 90. Geological Age. — Middle Permian (Leonardian). Locality.— USA: Texas, Road Canyon Formation, USNM loc. 72 lj, Glass Mts., West Texas. Location of Material.— Hypotype, USNM-330895. Remarks.— A fragmentary intermediate valve that is short, with a ridge radiating from the apex separating distinct lateral and central areas. Sur- face marked by prominent growth lines. Sutural laminae very broad and rounded. Indeterminate lepidopleurid genus and species C, Hoare and Smith, 1984:101, fig. 9P-V. Geological Age.— Middle Permian (Leonardian). Localities.— USA: Texas, Road Canyon Formation, USNM loc. 72 lj; Cathedral Mountain Formation, USNM loc. 709, Glass Mts., West Texas. Location of Material. — Hypotypes, USNM-330880- 330881. Remarks.— Two intermediate valves incom- plete along posterior margins. Valves slightly wider than long, low-arched with nearly straight side-slopes which are not divided into lateral and central areas. Possible false beak present. Sutural laminae short and broad. Jugal angle measures 1 1 5°. Surface ornamented with fine, closely spaced granules arranged in curved longitudinal rows. The most complete valve measured (mm): length, 7.0; width, 10.8; height, 4.0. Annotated Bibliography Ashby, E. 1929. Notes and additions to Australian fossil Polyplacophora (chitons). Proc. Royal Soc. Victoria, n.s. 4 1 (2): 220-230, pi. 24. [See pp. 228-229 for classification.] Baily, W. H. 1859. On the occurrence of detached plates of the shell of a new species of Chiton in the Carboniferous limestone at Lisbane, County of Limerick. Nat. Hist. Review and Quart. J. Sci. 6:330-334, pi. 28, fig. 2a-c. [Also: J. Geol. Soc. Dublin 8:167-171, pi. 4, fig. 2a-c, 1 860. Describes Chi- ton thomondiensis and lists 39 species of fossil chitons "at present known."] . 1860. Observations on two new species of Chiton from the Upper Silurian "Wenlock Limestone" of Dudley. Ann. and Mag. of Nat. Hist., ser. 3, 6(32):91-98, pi. 2, fig. la-d, 2a-c. [An English translation of de Koninck, 1857, q.v., with additional footnotes. Lists 35 species known to I860.] Barrande,J. 1867. Systeme Silurien du centre de la Boheme. Premiere partie: recherches paleontologiques, torn. 3. Classe des Mollusques. Ordre des Pteropodes. Pp. i-xv, 1-179, pi. 1-16. Prague and Paris. [See Appendix, p. 175, pi. 16, fig. 19-28b for Chiton bohemicus.] Barrois, C. E. 1 889. Faune du calcaire d'Erbray. Soc. Geol. Nord, Mem. 3:181, 182, pi. 15, fig. 15a-c. [Describes Hel- minthochiton lebescontei.] Batten, R. L. 1972. Permian gastropods and chitons from Perak, Malaysia. Pt. 1 : chitons, bellerophontids, euomphal- ids and pleurotomarians. Bull. Am. Mus. Nat. Hist. 147(1): 10, fig. 1-2. [Describes occurrence of three valves and illus- trates two of them. Bergenhayn, J. R. M. 1930. Kurze Bemerkungen zur Kennt- nis der Schalenstrucktur und Systematik der Loricaten. Kungl. Svenska Ventenskapsak., Handl., ser. 3, 9(3): 1-54, pi. 1-10. [Gives a classification of Recent and fossil polyplacopho- rans.] . 1943. Preliminary notes on the fossil polyplacoph- oras from Sweden. Geol. FQren. I Stockholm, Fdrh. 65(3): 297-303, text-fig. 1-3. [Describes a new order (Chelodina), two new families (Chelodidae, Scanochitonidae), two new genera (Scanochiton, Olingechiton), and two new species.] 1945. A new Carboniferous Lepidopleurus from Scotland. Geol. Foren. I Stockholm, Forh. 67(3):389-392, fig. 1-4. [Describes Lepidopleurus laterodepressus.] 1955. Die Fossilen Schwedischen Loricaten nebst einer vorlaufigen Revision des Systems der ganzen Klasse Loricata. Lunds Univ. Arsskrift, n.f, vd. 2, bd. 51, nr. 8. Kungl. Fysiogr. Sallskapets, Handl., n.f. 66(8):1-41, pi. 1- 2. [See pp. 40-41 for complete classification of fossil and Recent forms down to and including genera.] 1960. Cambrian and Ordovician loricates from North America. J. Paleontol. 34(1): 168- 178, text-fig. 1-20. [First published record of Cambrian polyplacophorans. Describes one new family (Preacanthochitonidae), one new genus (Preacanthochiton), and several new species. Repeats 1955 classification with additions and revisions.] Bigsby, J.J. 1878. Thesaurus devonico-carboniferus, pp. 3 1 8, 319. John Van Voorst, London. [Lists 22 species previously described from Europe and 2 from North America.] Billings, E. 1865. Paleozoic fossils, Vol. 1, containing de- SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 65 scriptions and figures of new or little known species of or- ganic remains from the Silurian rocks, 1861-1865. Geol. Surv. Canada p. 394, fig. 37a-c. [Chiton canadensis.] Bischoff, G. CO. 1981. Cobcrephora n.g., representative of a new polyplacophoran order Phosphatoloricata with cal- ciumphosphatic shells. Senckenbergiana Lethaea 61:1 73-2 1 5, pi. 1-7, text-fig. 1-6. Blainville, H. M. D. de. 1816. Prodrome d'une nouvelle distribution systematique du regne animal. Bull. Sci. Soc. Philomat. pp. 105-124. Paris. . 1825. Manuel de malacologie et de conchyliologie, Polyplaxiphora, pp. 601-603, Atlas, pi. 87, F. G. Levrault, Paris. Brady, L. F. 1955. Possible nautiloid mandibles from the Permian of Arizona. J. Paleontol. 29(1): 102-104, pi. 21, fig. 2-8. Branson, C. C. 1948. Bibliographic index of Permian in- vertebrates. Geol. Soc. Amer. Mem. 26:760-761. Bronn, H. G. 1848. Index Palaeontologicus oder Ubersicht der bis jetzt bekannten fossilen Organismen. 1st Abth., A, Nomenclator palaeontologicos, 1st Halfte, Chiton, pp. 291- 292. E. Schweizerbart, Stuttgart. [Also in later editions. Species references in synonymies are based on the 1848 edition, which lists 30 fossil species.] Burrow, E. I. 1815. Elements of conchology, according to the Linnean system, illustrated by 28 plates, drawn from nature. Ogles, Duncan and Cochran, London. 248 pp. Butts, C. 1926. Explanatory text to accompany the geolog- ical map of the state— the Paleozoic rocks. Geol. Surv. Ala., Spec. Rept. 14:99, 100, 125, 126, pi. 18, fig. 30-31; pi. 31, fig. 7. [Lists and illustrates Priscochitonl mirabilis and P.l sellaeformis.] . 1941. Geology of the Appalachian Valley in Virginia, Pt. 2. Va. Geol. Surv. Bull. 52:19-20, pi. 68, fig. 6. [Describes Hemithecella expansa.] Chenu, J. C. 1859. Manuel de conchyliogie et de paleonto- logie conchyliologique, Vol. 1, p. 379, fig. 2852. [Reference to Chiton priscus Miinster.] Clarke, J. M. 1885. Die Fauna des Ibergerkalkes. Neues Jahrbuch fur Mineralogie, Geologie und Palaontologie. HI. Beilage-Band, pp. 337-340, pi. 4, fig. 12-20. Stuttgart. [Sev- en species are covered.] . 1907. Some new Devonic fossils. New York State Mus., Bull. 107(12):194-195, 2 text-fig. [Describes Probo- laeuml canadense from the Lower Devonian of Quebec] Cloud, P. E. and V. E. Barnes. 1946. The Ellenburger group of central Texas. Univ. Texas Publ. 4621:140, 282, 365. [Mentions Lower Ordovician polyplacophoran plates, with no descriptions or figures.] Collett, J. 1879. Geological report on Harrison and Craw- ford counties, Indiana, 1878. Ind. Geol. Surv., 8th— 10th Annual Reports, 1876-78, p. 327. [Lists Chiton carbonarius Stevens.] Cossmann, A. E. M. and G. Pissaro. 1912. Revue critique de paleozoologie, Vol. 1 6, p. 2 1 7. [Refers to Raymond (1910) on Glaphurochiton (sic. = Glaphyrochiton).] Cotton, B. C. 1964. South Australian Mollusca— chitons- handbook of the flora and fauna of South Australia, issued by the South Australian Branch of the British Science Guild, Chap. 7, Fossil chitons, pp. 119-140, fig. 127-139, Adelaide. [Lists 76 names of which 65 are accepted as distinct species.] Cotton, B. C. and F. K. Godfrey. 1 940. The molluscs of South Australia— Australian fossil chitons. Handbook of the South Australian Museum, pt. II, p. 569-590, text-fig. 577- 589. British Association for the Advancement of Science, Adelaide. [Describes one new genus (Lavenachiton) and four new species. Gives a classification of fossil chitons. Lists 66 Australian fossil species by geological age excluding the Pleis- tocene. Notes only Permochiton australianus from the Pa- leozoic] Cumings, E. R. 1906. Fauna of the Salem Limestone— Gas- teropoda, Cephalopoda and Trilobita. Ind. Geol. Surv., 30th Annual Report, 1905, pp. 1 365-1 366, pi. 24, fig. 8-8c [Men- tions GryphochitonO) parvus (Stevens).] Dall, W. H. 1879. Report on the limpets and chitons of the Alaskan and Arctic regions, with descriptions of genera and species believed to be new. Scientific Results of the Explo- ration of Alaska, Art. 4, p. 97. [Also in: Proc U.S. Nat. Mus. 1:315 (1878). Brief mention of Paleozoic genera.] . 1 882. On the genera of chitons. Proc. U.S. Nat. Mus. 4:279-291 (1881). [Discusses Paleozoic chitons described up to 1873. Important for type designations.] Davidson, T. and W. King. 1874. On the Trimerellidae, a Paleozoic family of the palliobranchs or Brachiopoda. Quart. J. Geol. Soc. London 30(2): 124-1 72, pi. 18, fig. 14, 14a-c [Describes Chelodes bergmani n. gen., n. sp.] DeBrock, M. D., R. D. Hoare, and R. H. Mapes. 1984. Pennsylvanian (Desmoinesian) Polyplacophora (Mollusca) from Texas. J. Paleont. 58(4):11 17-1135, fig. 1-10. [De- scribes the new genera and species Camptochiton squarrosus, Pedanochiton discomptus, Pileochiton cancellus, and Cor- yssochiton parallelus and the species Helminthochiton sim- plex (Raymond), Pterochiton spatulatus Hoare, Sturgeon, and Hoare, Acutichiton pyrmidalus Hoare, Sturgeon, and Hoare and Arcochiton raymondi Hoare and Sturgeon.] Dechaseaux, C. 1952. Classe de Amphineures. Pp. 214- 215, fig. 3-4 in Traite de paleontologie, Vol. 2, J. Piveteau, ed. Masson et Cic, Paris. [Brief discussion of the distribution by geological age. Estimates the occurrence of about 250 fossil species.] Dunlop, R. 1915. Notes on the discovery of fossil chitons in Fife. Trans. Geol. Soc. Glasgow 15(2): 167-1 73, pi. 22, fig. 1-6. [Describes Chiton woodmillensis. Discusses and fig- ures three other Carboniferous species.] . 1922. Notes on the chitons of Woodmill. Trans. Geol. Soc Glasgow 17:75-76, text-fig. 1. [Comments on the collection of over 80 valves in a small area, comprising three species.] Eberzin, A. G. 1960. Mollusca— Loricata, Bivalvia and Sca- phopoda. Fundamentals of paleontology, Vol. 3, Loricata, pp. 15-17, text-fig. 1. Academy of Sciences of the USSR, Moscow. In Russian. [Brief mention of fossil species with a figure of Helminthochiton, presumably H. priscus (Miins- ter).] Eichwald, E. d'. 1860. Lethaea Rossica ou Paleontologie de la Russie, Vol. 1, sec. 3, p. 1093. Stuttgart. [Mentions Chiton priscus Miinster.] Etheridge, R., Jr. 1882. A contribution to the study of the British Carboniferous Chitonidae. Proc. Nat. Hist. Soc. Glasgow 5:84-107, pi. 1-2. [Describes seven new species; covers eight others, with figures.] . 1897. On the occurrence of the genus Chelodes, Da- vidson and King, in the Upper Silurian of New South Wales. Records of the Geological Survey of New South Wales, Vol. 5, pt. 2, pp. 67-70, text-fig. A-F. [Describes Chelodes cal- ceoloides.] Fischer, P. 1885. Manuel de conchyliologie et de paleon- tologie conchyliogique ou histoire naturelle des mollusques 66 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 vivantset fossiles— Ordredes Polyplacophora. Pp. 870-884, text-fig. 613-625, pi. XI, fig. 28-3 1 . [For comment on Fisch- er's classification, see Pilsbry, 1892, Manual of conchology, Vol. 14, p. xxi.] Fischer, P.-H. 1957. Revision des Amphineures de la Col- lection de l'Ecole des Mines de Paris. J. Conchyl. 97(1): 10— 24. [Lists 1 6 fossil species. This collection includes de Ko- ninck's from the Paleozoic, Bourdot's from the Tertiary, and Deshayes's from the Recent. It would appear that some of Rochebrune's Eocene species from the Paris Basin are here also. Much of the material has been figured by Cossmann (1888) and by Cossmann and Pissaro (1910-1913).] Fisher, D. W. 1962. Small conoidal shells of uncertain af- finities. Pp. 98-143 in Treatise on invertebrate paleontology, Pt. W, Miscellanea, R. C. Moore, ed. Geol. Soc. America and Univ. Kans. Press, Lawrence, Kansas. Flower, R. H. 1968. Some El Paso guide fossils. New Mexico Instit. Mining and Tech., Mem. 22, pt. 1, pp. 1-19, pi. 1, fig. 1-24. [Describes Calceochiton hachitae n. sp. (type of Calceochiton n. gen.) and C. cf. C. gibberosum (Sardeson).] Foster, J. W. 1837. Miscellaneous observations made during a tour in May, 1835, to the Falls of the Cuyahoga [Ohio], near Lake Erie: extracted from the diary of a naturalist. Amer. J. Sci. 31(l):82-84, fig. 20. [Describes Chiton occi- dentalis with 10 valves; a cephalopod not a polyplacopho- ran.] Fraas, E. 1910. Der Petrefaktensammler. Schriften der Deutschen Lohrerver fur Naturwissenschaft, Bd. 25, p. 83, fig. 55. Stuttgart. [Fig. 55 is of Gryphochiton priscus (Minis- ter).] Frederickson, E. A. 1956. Rare fossil chiton from Ada, Oklahoma. Okla. Geology Notes, Okla. Geol. Surv. 16(7): 65-66, fig. 1. [Notice of a new Helminthochiton with valves i-vi, inclusive, in place.] . 1962. Helminthochiton from the Pennsylvanian of Oklahoma, Okla. Geology Notes, Okla. Geol. Surv. 22(1 1): 298-302, fig. 1-3. [Describes Helminthochiton riddlei.} Geinitz, H. B. 1846. Grundriss der Versteinerungskunde, Vol. 1, Fam. Chitonidae, p. 389, pi. 5, fig. 13-14. Dresden and Leipzig. [Reference to Chiton priscus Miinster and ?C. cottae Geinitz.] . 1861. Die animalischen Ueberreste der Dyas. Dyas oder de Zechsteinformation und das Rothliegende, Heft. 1 , pp. 53-56, text-fig. VI(1-10), VII(1-1 1), VIII(l-lO). Leipzig. [Comments on seven species, including Chiton cottae.] Girty,G.H. 1909. The Guadalupian fauna. U.S. Geol. Surv. 58:450-451, pi. 29, fig. 21, 21a. [For Cymatochitonl texanus n. sp. from the Texas Permian.] Gortani, M. 1913. La Serie Devoniana nella Giogaia del Coglians (Alpi Carniche). Bolletino Roma Comitato Geo- logico d'ltalia, ser. 5, 43:262, pi. 3, fig. 13a-b (1912). [De- scribes Chiton collinensis from the Upper Devonian of Aus- tria.] Gray, J. E. 1847a. On the genera of the family Chitonidae. Proc. Zool. Soc. London, pt. 15, no. 174, p. 70. [Describes the genus Gryphochiton.] . 1 847ft. A list of the genera of Recent Mollusca, their synonyms and types. Proc. Zool. Soc. London, pt. 15, no. 178, p. 169. [Chiton nervicanus de Ryckholt, 1845 desig- nated as type species of Gryphochiton Gray, 1847.] Gurich, G. 1929. Silesicaris von Leipe und die Phylloka- riden uberhaupt. Mitteil. Mineral-geol. Staatsinst. Hamburg 1 1:49. [Compares Anatifopsisl elongata with Solenocaris.] Hadding, A. 1913. Undre DicellograptusskifTern i Skane jamte nagra darmed ekvivalenta bildningar. Lunds Univ. Arsskrift, n.f. 2, 9(15):67, pi. 4, fig. 34. [Describes Anatifop- sis? elongata.] 1915. Der mittlere Dicellograptus Schiefer auf Born- holm. Lunds Univ. Arsskrift, n.f. 2, 11(4):31, pi. 4, fig. 27. [Describes Anatifopsis? elongata.] Herrmannsen, A. N. 1852. Indicis generum malacazoorum primordia. Supplementa et corrigenda, p. 58. Cassellis, Lon- don and Paris. [Mentions genus Gryphochiton, type G. ner- vicanus.] Hoare,R.D. 1975. Selection of neotype specimen for Chiton carbonarius Stevens (Mollusca, Polyplacophora). Ohio J. Sci. 75(5):223-224, fig. 1-3. . 1976. Lobarochiton, new generic designation for Gry- phochiton"! anomalus (Rowley) (Polyplacophora). Ohio J. Sci. 76(3): 116-1 18, fig. 1-3. Hoare, R. D. and R. H. Mapes. 1985a. New Mississippian and Pennsylvanian Polyplacophora (Mollusca) from North America. J. Paleontol. 59(4):875-881, fig. 1-3. [Describes Colapterochiton decorus n. gen., n. sp.; Elachychiton jux- taterminus n. gen., n. sp.; and Euleptochiton torus n. gen., n. sp.] . 1985ft. A new species of Pennsylvanian Polypla- cophora (Mollusca) from Texas. J. Paleontol. 59(5): 1324- 1326. [Describes Acutichiton pannuceus.] Hoare, R. D., R. H. Mapes, and D. E. Atwater. 1983. Pennsylvanian Polyplacophora (Mollusca) from Oklahoma and Texas. J. Paleontol. 57(5):992-1000,fig. 1-5. [Describes Pterochiton carbonarius (Stevens), P. tholus and Acutichiton allynsmithi. Proposed new family Acutichitonidae.] Hoare, R. D. and A. G. Smith. 1984. Permian Polypla- cophora (Mollusca) from West Texas. J. Paleontol. 58(1): 82-103, fig. 1-10. [Describes the new species Helmintho- chiton girtyi and the new genera and species Ochmazochiton comptus, Chauliochiton knight i, Stegochiton coxi, S.l one- rosus, Soleachiton yochelsoni, Lekiskochiton fornicis, and three indeterminate genera and species. Proposed new family Ochmazochitonidae.] Hoare, R. D. and M. T. Sturgeon. 1976. Arcochiton ray- mondi n. gen., n. sp. of polyplacophoran from the Pennsyl- vanian of Ohio. J. Paleontol. 50(5):841-845, pi. 1-2. . 1979. Stratigraphic distribution of Polyplacophora in the Mississippian and Pennsylvanian of North America. 8th Internat. Congr. Carb. Strat. and Geology, Compte Ren- du 3: 1 76-1 83, pi. 1-3. [Shows distribution of seven species.] Hoare, R. D., M. T. Sturgeon, and T. B. Hoare. 1972. Middle Pennsylvanian (Allegheny Group) Polyplacophora from Ohio. J. Paleontol. 46(5):675-680, pi. 1-3. [Describes Pterochiton carbonarius (Stevens), Helminthochiton simplex (Raymond), Pterochiton spatulatus n. sp., Acutichiton pyr- midalus n. gen., n. sp.] Howse, R. 1848. A catalogue of the fossils of the Permian System of the Counties of Northumberland and Durham. Trans. Tyneside Nat. Field Club 1:219-264. [Describes Ca- lyptraea antiqua {=Chiton antiquus) Howse and Chiton sp.] . 1857. Notes on the Permian System of the Counties of Durham and Northumberland. Ann. and Mag. Nat. Hist., ser. 2, 19:426-476, pi. 4, fig. 16- 17. [Also in: Trans. Tyneside Nat. Field Club 3:235-285, pi. 1 1 (1858). Discusses Chiton loftusianus King and Calyptraea antiqua Howse.] Iredale, T. and A. F. B. Hull. 1926. A monograph of the Australian loricates, VIII, Appendix B, Paleoloricata. Aus- tral. Zool. 4(5):324-328, pi. 45. [Reprinted in: Royal Zool. SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 67 Soc. New South Wales, pp. 139-143, pi. 18(1927). A review of all Australian fossil species.] Jaekel, O. 1 900. Uber einem neuen Chitonida Trachypleura n.g. aus dem Muschelkalk von Rudersdorf. Zeitschr. Deutsch. Geol. Gesell. 52:9-14, fig. 1-2. [Mentions Chiton tornacicola de Ryckholt and C. scaldianus de Ryckholt.] Jahn, J. J. 1893. Duslia eine neue Chitonidengattung aus dem bomischen Untersilur, nebst einigen Bemerkungen uber die Gattung Triopus Barrande. Sitzungberichte der mathe- matisch-naturwissenschaftlichen Klasse der Kaiserlichen Academie der Wissenschaften zu Wien, Abth. 2, Bd. 102, Heft 8, pp. 591-603, pi. 1, fig. 1-4. [Describes Duslia insig- nis, from the Lower Silurian of Bohemia.] Kjndle, E. M. 1898. A catalogue of the fossils of Indiana. Ind. Dept. Geology and Nat. Resources, 22nd Ann. Rept. for 1897, p. 468. [Lists Chiton carbonarius Stevens.] King, W. 1844. The genus Chiton found in the Magnesian Limestone of Durham. Ann. and Mag. Nat. Hist., ser. 1 (new series) 14(92):38 1-382. [First report of the occurrence of a polyplacophoran in the Permian.] . 1846. On a Magnesian-Limestone species of Chiton. Charlesworth's London J. Geology 1:10-12, fig. 1-4. . 1 848. A catalogue of the organic remains of the Perm- ian rocks of Northumberland and Durham, 16 pp. William King, Newcastle-upon-Tyne. [Describes Chiton loftusianus.] . 1850. A monograph of the Permian fossils of En- gland. Paleontogr. Soc, pp. 201-203, 247 (Appendix), pi. 16, fig. 9-14. [Describes Chiton loftusianus; comments on the validity of Calyptraea antiqua Howse.] Kjrkby, J. W. 1857. On some Permian fossils from Durham. Quart. J. Geol. Soc. London 13:213-218, pi. 7, fig. 9-13. [Also in: Trans, of the Tyneside Nat. Field Club 3:286-294, pi. 12, fig. 9-13 (1858). Describes Chiton howseanus.] . 1859. On the Permian Chitonidae. Quart. J. Geol. Soc. London 15:607-626, pi. 16, fig. 1-52. [Also in: Trans, of the Tyneside Nat. Field Club 3:238-263, pi. 13, fig. 1-52 (1860). Describes Chiton? cordatus, Chitonellus hancocki- anus, and C distortus. Lists and illustrates three other species.] . 1862. On some remains of Chiton from the Moun- tain-Limestone of Yorkshire. Quart. J. Geol. Soc. London 18:233-237, text-fig. 1-10. [Describes several new species from the Carboniferous of England and lists 1 5 other species from the Carboniferous of Europe.] 1864. On some fossils from the Lower Magnesian Limestone of Sunderland. Trans. Tyneside Nat. Field Club 4:212-220. [Mentions Chiton loftusianus?.] Kjrkby, J. W. and J. Young. 1867. Notes on some remains of Chiton and Chitonellus from the Carboniferous strata of Yorkshire and the west of Scotland. Geol. Mag. 4(38):340- 343, pi. 16, fig. 1-17. [Describes nine species.] Knorre, H. von. 1925. Duslia insignis Jahn— ein angeblich 1 1 oder 12 Schalenplatten tragender Chiton der untersilur- ischen Schichten Bohmens. Jenaische Zeitschrift fur Natur- wissenschaft, Bd. 61, pp. 497-499, text-fig. 1. Koninck, L. G. de. 1842. Description des animaux fossiles, qui se trouvent dans le terrain carbonifere de Belgique. Le genre Chiton Linn., pp. 60-61, 319-324, pi. 22, fig. 4-5 and pi. 23, fig. 1-2. H. Dessain, Liege. [Describes Chiton priscus and the new species C. concentricus, C gemmatus, and C.I cordifer.] . 1883. Faune du calcaire carbonifere de la Belgique, Pt. 4, Gasteropodes. Annales Musee Royale d'Histoire Na- turelle de Belgique, ser. Paleont. 8(4): 198-2 13, pi. 50-53. [Describes new genera Rhombichiton and Glyptochilon and describes 16 species.] Koninck, M. L. de. 1857. Sur deux nouvelles especes silu- riennes appartenant au genre Chiton. Bulletin de FAcademie Royale des Sciences, des Lettres et des Beaux-Arts de Bel- gique 11:190-199, pi. 1, fig. la-d, 2a-c. Brussels. [Reviews existing knowledge of fossil chitons and lists them by geo- logical age. Describes Chiton grayanus and C wrightianus. See Baily (1860) for English translation.] . 1860. Observations on two new species of Chiton from the Upper Silurian "Wenlock limestone" of Dudley. Ann. and Mag. Nat. Hist., ser. 3, 6(32):91-98, pi. 2. [De- scribes Chiton grayanus and C wrightianus and lists all known species to date.] Kues, B. S. 1978. Polyplacophora from the Salem Limestone (Mississippian) in central Indiana. J. Paleontol. 52(2):300- 310, pi. 1-2, text-fig. 1. [Describes Pterochiton parvus (Ste- vens) and P. elevatus.] . 1983. A chiton from the Flechado Formation (Mid- dle Pennsylvanian) of northern New Mexico. New Mexico J. Sci. 23(1): 19-21, 1 text-fig. [Describes an occurrence of Pterochiton carbonarius.] Ladd, H. S. 1925. The stratigraphy and fauna of the Ma- quoketa shale of Iowa. Univ. Iowa. Unpublished Ph.D. The- sis. [Notes Ceratiocaris cf. C. (Limnocaris) praecedens (=Septemchiton iowensis) from the Upper Ordovician, pp. 205-206, pi. 32, fig. 23-24.] Lamarck, J. P. D. M. de. 1802. Memoires sur les fossiles des environs de Paris, comprenant la determination des es- peces qui appartiennent aux animaux marins sans vertebres et dont la plupart sont figures dans la collection de velins du Museum. Premier Memoire, Genre I, Chiton. Oscabrion. Annales du Musee Nationale Naturelle, Vol. 1, p. 308. Paris. [First published account of a fossil chiton (C. grignonensis).] Lang, V., J. Marek, and I. Pek. 1982. A find of the species Rhombichiton laterodepressus (Bergenhayn, 1 945) in the Culm of the Drahanska vrchovina Upland. Vestnik Ustredniho ustava geologickeho 57(5):299-302, pi. 1-2. Lesley, J. P. 1 889. A dictionary of the fossils of Pennsylvania and neighboring states named in the reports and catalogues of the Survey. Pa. 2nd Geol. Surv., Rept. P4, vol. 1-3, 1283 pp. Lindstrom, G. 1884. On the Silurian Gastropoda and Pter- opoda of Gotland. Chitonidae. Kongl. Svenska Vetenskaps- Akad., Handl. 19(6):48-52, pi. 2, fig. 1-27. Stockholm. [Gives reasons for including Chelodes in the Chitonidae. Describes Chelodes gotlandicus.] Linne, C. 1764. Museum Ludovicae Ulricae Reginae Sue- corum, Gothorum, Vandalorumque ... in quo animalia rar- iora, exotica, imprimis insecta & conchilia describuntur & determinantur. Direct. Laur. Salvii, Stockholm. 720 pp. McCoy, F. 1846. Synopsis of the Silurian fossils of Ireland. Addenda, p. 71, pi. 5, fig. 5a-e. [Describes Helminthochiton griffithi Salter.] Marek, L. 1962. New polyplacophorid family Eochelodidae n. fam. in the Ordovician of Bohemia. Vestnik Ustredniho ustavu geologickeho 38:373-375, 1 pi., text-fig. 1. [Describes Eochelodes bergenhayni.] Meek, F. B. and A. H. Worthen. 1873. Fossils of the Coal Measures. Geol. Surv. 111. 5(2):560-619, pi. 29, fig. 15. [De- scribes Chiton carbonarius Stevens.] Mendes, J. C. 1952. Invertebres du systeme de Gondwana au Br6sil. Pp. 302-307 in Symposium sur les series de Gond- 68 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 wana, XlXth Congr. Geol. Internat. [Reports a valve of Chiton sp. from the Permian of Brazil.] Miller, S. A. 1889. North American geology and paleon- tology for the use of amateurs, students and scientists. West- ern Methodist Book Concern, Cincinnati. 664 pp. Moore, R. C, C. G. Lalicker, and A. G. Fischer. 1952. Invertebrate fossils. Chitons, pp. 271-273, fig. 2a-c, 3. McGraw-Hill Book Co., Inc., New York. [Brief review of fossil chiton occurrences.] Morris, N.J. 1967. Amphineura. P. 424 in The fossil record. W. B. Harland et al., eds. Geol. Soc, London. Munster, G. G. zu. 1839. Der Chiton priscus und einige andere seltens Versteinerungen aus der Uebergangsforma- tion. Beitrage zur Petrefactenkunde, 1st ed. 1839, Vol. 1, p. 38, pi. 13, fig. 4; 2nd ed., 1843, Vol. 1, pp. 60-61, pi. 13, fig. 4a-e. Buchner'schen Buchhandlung, Bayreuth. [De- scribes Chiton priscus.] Nicolaus, H. J. 1963. Zur Stratigraphie und Fauna der Crenestria-Zom im Kulm des Rheinischen Schiefergebirges. Beihefte zum Geologischen Jahrbuch 53:203, 205, pi. 16, fig. 2a-g, 3; pi. 18, fig. 5. [Mentions Helminthochiton priscus and Lepidopleurus laterodepressus.] Oehlert, M. D. 1881. Documents pour servir a l'etude des faunes Devoniennes dans l'ouest de la France. Mem. Soc. Geol. France, ser. 3, 2(1): 15-1 7, pi. 2, fig. 3a-b. Paris. [De- scribes two new genera, Sagmaplaxus and Beloplaxus, and one new species, S. sarthacensis.] Orbigny, A. D. d\ 1 850. Prodrome de paleontologique stra- tigraphique universelle des animaux mollusques et rayonnes faisant suite au cours elementaire de paleontologie, Vol. 1, p. 127. Victor Masson, Paris. [General reference to genus Chiton and to species by Etage number, and species number. Chiton priscus, C concentricus, C subgemmatus, Chitonel- lus cordifer.} Pictet, F. J. 1844. Traite de paleontologie ou histoire na- turelle des animaux fossiles consideres dans leurs rapports zoologiques et geologiques. 1st ed., Vol. 3, p. 300; 2nd ed., 1855, Vol. 3, Les oscabrions (Chiton, Linn., Cryptoplax Gray), pp. 300-302, Atlas, pi. 69, fig. 18-19. J.-B. Bailliere et fils, Paris. [Lists and comments on a number of fossil species from the Devonian, Carboniferous, Permian, Jurassic, and the Tertiary.] Pilsbry, H. A. 1892. Monograph of the Polyplacophora: manual of conchology 14:1-350, pi. 1-68. Academy of Nat. Sci., Philadelphia. . 1900. Amphineura. Pp. 433-436 in Textbook of pa- leontology, Eastman translation, K. A. von Zittel, ed. [Also, 2nd ed., 1913, pp. 510-513, text-fig. 841-842]. MacMillan and Co., London. [Classifies the Paleozoic genera under a new family (Gryphochitonidae). Discusses Dusilia insignis Jahn.] Plas, L. F., Jr. 1972. Upper Wolfcampian(?) Mollusca from the Arrow Canyon Range, Clark County, Nevada. J. Pa- leontol. 46(2): 249-260, 1 pi. [Mentions presence of Hel- minthochiton sp. and an unknown genus and species.] Pompeckj, J. F. 1912. Amphineura— Palaontologie. Hand- worterbuch der Naturwissenschaften, Vol. 1, pp. 354-357, text-fig. 1-3. Gustav Fischer, Jena. [A short general review of fossil polyplacophorans. Discusses Duslia insignis Jahn.] Quenstedt, F. A. 1852. Handbuch der Petrefaktenkunde. P. 445. H. Laupp, Tubingen. [Describes Chiton priscus Munster.] . 1882. Petrefaktenkunde Deutschlands-Gasteropo- Quenstedt, W. 1931. Loricata (Palaontologie). Handworter- buch Naturwissenschaften, 2nd ed.. Vol. 6, pp. 552-555, fig. 1-3. Gustav Fischer, Jena. . 1932. Die Geschichte der Chitonen und ihre allge- meine Bedeutung. Palaont. Zeit. 14(l-2):77-96, text-fig. 1. [A useful summary of existing knowledge, with references to earlier literature.] Quoy, J. R. C. and J. P. Gaimard. 1835. Voyage de decou- vertes d' Astrolabe. Zoologie, Vol. 3, 954 pp., 9 pi. Pillet aine, Paris. Raymond, P E. 1910. A preliminary list of the fauna of the Allegheny and Conemaugh series in western Pennsylvania. Ann. Carnegie Mus. 7(1): 153-1 54, pi. 24, fig. 1 1-12, pi. 26, fig. 6, pi. 28, fig. 14-16. [Describes genus Glaphurochiton, with C carbonarius (Stevens) as type species, and Glaphu- rochiton simplex.] . 1911. Pa. Topo. and Geol. Surv., Rept. for 1908- 1910, pp. 83-98, pi. 3, fig. 11, 12; pi. 5, fig. 4. [Lists and illustrates Glaphurochiton simplex and G. carbonarius.] Reed, F. R. C. 1907. Sedgwick Museum Notes. Crustacea, etc., from Girvan. Geol. Mag., ser. 2, decade 5, 4:1 13-1 14, pi. 4, fig. 8-14. [Lists Helminthochiton grayiae Woodward, 1885 and Chiton sp. from the Lower Silurian.] . 1911. A new fossil from Girvan. (I.— Sedgwick Mu- seum Notes). Geol. Mag., decade 5, 8(8):337-339, pi. 15. [Describes Helminthochiton thraivensis from the Upper Or- dovician. Figures 7, 7c show girdle spicules.] Reeve, L. A. 1847. Monograph on the genus Chiton. Con- chologia iconica, Vol. 4, pi. 1-28, fig. 1-194. Reeve Brothers, London. Reso, A. 1963. Composite columnar section of exposed Pa- leozoic and Cenozoic rocks in the Pahranagat Range, Lincoln County, Nevada. Bull. Geol. Soc. Am. 74(7):901-918, pi. 2. [Lists Matthevia sp. from the Desert Valley Formation.] Rhoads, D. C. 1962. Microfossils of problematical affinity from the Maquoketa Formation of eastern Iowa and western Illinois. J. Paleontol. 36(3): 1334-1 340, text-fig. 1A-D, 2A- D, 3A-B, pi. 178, fig. 1-16. [Describes three new genera (Bursata, Subcylindrica, Triangulata) and six new species of tegmates from the Upper Ordovician, subsequently de- scribed as polyplacophoran. See Sanders (1965).] Richardson, E. S., Jr. 1956. Pennsylvanian invertebrates of the Mazon Creek area, Illinois. Fieldiana: Geology, Chi- cago Nat. Hist. Mus. 12(3):61-65, fig. 34-36. [Describes Helminthochiton concinnus. Figures show impression of radula.] Robson, G. C. 1913. Helminthochiton aequivoca, n. sp., Lower Ordovician, Bohemia. Geol. Mag., decade 10, 10:302-304, text-fig. 1-3. Rochebrune, A. T. de. 1883. Monographie des especes fos- siles appartenant a la Classe des Polyplaxiphores. Annales des Sciences/Geologiques, Vol. 14, Art. 1, pp. 1-74, pi. 1- 3. Paris (1882). [A general account, listing 69 species con- sidered valid, by geological age, and 30 Species incertae. Describes 25 new Tertiary species. Most of Rochebrune's descriptions and figures are inadequate and cannot be used for reliable identification.] Roemer, C. F. von. 1851. Kohlen Periode (Silur-, Devon-, Kohlen- und Zechstein-Formation, 2. Palaeo-Lethaea. Bd. 1 , Theil II, pp. 447-448, pi. 3, fig. 1 8 in Lethaea Geognostica oder Abbildung und Beschreibung der fur die Gebirgs- Formationen bezeichnendsten Versteinerungen, H. G. Bronn and C. F. Roemer. E. Schweizerbart, Stuttgart. . 1876. Lethaea geognostica oder Beschreibung und den, Vol. 7, 867 pp.. Atlas, pi. 186-218. L. F. Fues, Leipzig. Abbildung der fur die Gebirgs-Formationen bezeichnend- SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 69 sten Versteinerungen, Theil I, Lethaea Palaeozoica, Bd. 1, Atlas, pi. 45, fig. 22. J. C. Henzler, Stuttgart. [Gives an illustration of Chiton priscus Munster.] Roemer, F. A. 1843. Die Versteinerungen des Harzgebirges. P. 32, pi. 9, fig. 5. Hahn, Hannover. [Bellerophon expansus Sowerby — a polyplacophoran according to de Koninck (1883, p. 199).] . 1855. Beitrage zur geologischen Kenntniss des nord- westlichen Harzgebirges. Palaeontogr. 5(1):36, pi. 7, fig. 8a- b, 9a-b, pi. 22, fig. 9. [Describes Chiton laevigatus.] Rolfe, I. W. D. 1981. Septemchiton—a misnomer. J. Pa- leontol. 55(l):675-678, text-fig. 1-3. Rowley, R. R. 1908. The geology of Pike County. Mo. Bur. Geology and Mines, 2nd ser., 8:90, pi. 19, fig. 15-19. [De- scribes Platyceras? anomalum.} Runnegar, B. and J. Pojeta, Jr. 1974. Molluscan phylog- eny: the paleontological viewpoint. Science 186(4 161): 31 1- 317, fig. 3A-0, 4-5. [Illustrates Chelodes sp. from the Or- dovician of Australia.] Runnegar, B., J. Pojeta, Jr., M. E. Taylor, and D. Collins. 1 979. New species of the Cambrian and Ordovician chitons Matthevia and Chelodes from Wisconsin and Queensland: evidence for the early history of polyplacophoran mollusks. J. Paleontol. 53(6): 1374-1 394, pi. 1-3, text-fig. 1-4. [De- scribes Matthevia variabilis Walcott, Matthevia walcotti n. sp., Chelodes whitehousei n. sp., Helminthecella expansa Ul- rich and Bridge, and Preacanthochiton cooperi Bergenhayn]. Ryckholt, P. de. 1845. Resume geologique sur le genre Chiton Lin. Bulletin de l'Academie Royale des Sciences et des Belles-Lettres de Bruxelles 12(7): 36-62, pi. 1-4. [An important contribution describing 1 1 new Paleozoic species and commenting on 4 already described. Lists 2 Tertiary species.] . 1852. Melanges Pal6ontologiques — Chitonidae. Memoires Couronnes et Memoires des Savants etrangers. L'Academie Royale des Sciences, des Lettres et des Beaux- Arts de Belgique 24:63-65, pi. 2, fig. 35-38 (1850-51). [De- scribes Chiton scaldianus, C slusianus, and C. barrandean- us.] . 1862. Description de deux tuniciers carboniferes et d'un nouveau genre de la famille des Chitonidae. J. Conchyl., ser. 3, 2(3):259-260, pi. 12, fig. 14. [Describes Sulcochiton grayi. Probably not a polyplacophoran.] Salter, J. W. 1847. Description of a fossil chiton from the Silurian rocks, with remarks on the fossil species of the genus. Quart. J. Geol. Soc. London 3:48-52, text-fig. 1-6. [De- scribes genus Helminthochiton and gives a list of fossil species.] Sandberger, F. 1845. Kurtze Bemerkungen zu der Schrift von F. A. Roemer: "die Versteinerungen des Harz-Gebirges, mit XII Steindruck-Tafeln. Hannover, 1 843." Neues Jahr- buch fur Mineralogie, Geognosie, Geologie und Petrefakten- Kunde, p. 439. Stuttgart. [For Chiton cordiformis.] Sandberger, G. 1842. Vorlaufige Ubersicht iiber die eigen- thiimlichen bei Villmar an der Lahn auftretenden jiingeren Kalk-Schichten der alteren (sog. Uebergangs-) Formation, besonders nach ihren organischen Einschliissen, und Be- schreibung ihrer wesentlichsten neuen Arten nebst einem Vorwert iiber Namengebung in der Naturbeschreibung iiber- haupt und in der Paleontologie insbesondere. Neues Jahr- buch fur Mineralogie, Geognosie, Geologie und Petrefakten- Kunde, 1 842, pp. 387, 399. Stuttgart. [Describes Chitonpris- cus Munster, C. subgranosus, and C fasciatus as new.] Sandberger, G. and F. Sandberger. 1856. Die Verstei- nerungen des Rheinischen Schichten Systems in Nassau. Ge- nus Chiton, pp. 237-240, pi. 26, fig. 22, 22a-d, 23, 23a-d. Quarto, 1850-56. Kreidel and Niedner, Wiesbaden. [De- scribes Chiton corrugatus and C sagittalis from the Devo- nian.] Sanders, R. B. 1962. Conodonts of the Beaverfoot-Brisco formations, Ordovician of British Columbia. Unpublished Masters Thesis, 102 pp., Univ. Iowa. [For microfossils ques- tionably similar to Septemchiton iowensis Sanders, 1965. Noted as tegmates, Bursata iowensis.] . 1965. A new species of Septemchiton. Proc. Okla. Acad. Sci. for 1964, pp. 94-98, fig. 1-12. [Describes Sep- temchiton iowensis from the Upper Ordovician.] Sardeson, F. W. 1896. The fauna of the Magnesian series. Bull. Minn. Acad. Nat. Sci. 4(1): 102, pi. 6, fig. 8-10. [De- scribes Ascoceras gibberosum.] Schmidt, H. 1951. Neue Faunen aus dem Namur des nord- ostlichen Spaniens. Palaontol. Zeitschr. 24:184-193, pi. 13, fig. 11. [Lists and figures Helminthochiton aft", gemmatus (de Koninck).] Shimer, H. W. and R. R. Shrock. 1944. Index fossils of North America. Order Polyplacophora, pp. 526-527, pi. 216, fig. 1-37. John Wiley & Sons, Inc., New York. [A review of fossil polyplacophoran genera, with their geological age dis- tribution.] Simroth, H. 1893. Amphineura. Pp. 311-313, 351, text-fig. 37, 40 in Klassen and Ordnungen des Tier-Reichs, Bd. 3, Mollusca (Weichtiere), H. G. Bronn, ed. C. F. Winter, Leip- zig and Heidelberg. [Brief discussion of fossil records. Illus- trates Gryphochiton priscus Munster, and Dusliae insignis Jahn.] Sirenko, V. I. and Y. I. Starobogatov. 1977. K sistematike paleozoyskikh i mezozoyskikh khitonov. Paleontol. Zhur. 3:30-41, fig. 1-3. [English translation by the Amer. Geol. Inst., Paleontol. Journal 1 1(3):285-294, fig. 1-3, 1977.] Smith, A. G. 1960. Amphineura. Pp. 141-176, fig. 31-45 in Treatise on invertebrate paleontology Part I, Mollusca 1, R. C. Moore, ed. Geol. Soc. Amer. and Univ. Kans. Press, Lawrence, Kansas. [A general account, with a systematic classification including all described genera with their type species.] . 1971. The Carboniferous genus Glyptochiton de Koninck, 1883 (Mollusca: Polyplacophora). Proc. Calif. Acad. Sci., 4th ser., 37(22):567-574, fig. 1-15. . 1973. Fossil chitons from the Mesozoic— a check- list and bibliography. Calif. Acad. Sci., Occas. Paper 103, 30 pp. . 1976. Two new Permian chitons from West Texas (Mollusca: Polyplacophora). The Veliger 18(3):28 1-288, fig. 1-34. [Describes Pterochiton arthurcooperi and P. newelli.] Smith, A. G. and D. F. Toomey. 1964. Chitons from the Kindblade Formation. Okla. Geol. Surv., Cir. 66:1-41, pi. 1-8, text-fig. 1-2. [Describes two new genera, Paleochiton and Eochiton, and five new species from the Lower Ordo- vician.] Sowerby, J. de C. 1839. Fossil shells in the lowest beds of the Old Red Sandstone and fossil shells of the upper Ludlow rock. Pp. 602-604, 608-613, pi. 5, fig. 32 in The Silurian System, R. I. Murchison, ed. John Murray, London. [Bel- lerophon expansus.] Spinar, Z. 1965. Systematicka paleontologie bezobratlych, pp. 318-320, fig. VIII-8-9, Academia Nakladatelstvi Ces- koslovenske Academie Ved, Praha. [Short discussion of clas- sification and illustrates Chelodes bohemicus (Barrande) and Helminthochiton? secundus Horny.] Starobogatov, Y. I. and V. I. Sirenko. 1975. The system 70 OCCASIONAL PAPERS OF THE CALIFORNIA ACADEMY OF SCIENCES, No. 146 of the Polyplacophora. Pp. 21-23 in The Mollusca, their system, evolution and natural role, fasc. 5. Nauka Press. Stevens, R. P. 1858. Description of new Carboniferous fos- sils from the Appalachian, Illinois, and Michigan coalfields. Amer. J. Sci. and Arts, ser. 2, 25(74):264. [Describes Chiton carbonarius and C. parvus.] Stmt, B. and C. Burrett. 1984. Early Ordovician polypla- cophoran Chelodes whitehousei from Tarutao Island, south- em Thailand. Alcheringa 8:1 12, fig. 1. Stromer von Reichenbach, E. 1 909. Lehrbuch der Palaozo- ologie. I, Wirbellose Tiere, pp. 196-197, fig. 230. Leipzig and Berlin. [Gives an illustration of Gryphochiton priscus (Minister).] Stuckenberg, A. 1898. Allgemeine geologische Karte von Russland. Blatt. 1 27. Russia, Geologicheskii Komitet, Trudy (Comite geologique, Memoires), Vol. 16, no. l,pp. 163,364, pi. 3, fig. 25a-b. [Lists and figures Chitonellus antiquus (Howse).] Thiele, J. 1909. Revision des Systems der Chitonen. Zoo- logica. Vol. 22, no. 56, pp. 1-70, pi. 1-6, text-fig. 1-5; 1910, pp. 71-132, pi. 7-10. Trenkner, W. 1 868. Palaontologische Novitaten von Nord- westlichen Harze. I. Ibergerkalk und Kohlengebirge von Grand. Abhandlungen der Naturforschenden Gesellschaft zu Halle, Bd. 10, Chitons, pp. 135-138, pi. 2, fig. 26-33. [Describes seven new species from the Upper Devonian and lists two already described. Figures are extremely stylized enlargements and their identification as polyplacophorans from these is questionable.] Tryon, G. W., Jr. 1883. Manual of structural and systematic conchology. An introduction to the study of the Mollusca, Vol. 2, pp. 339-340, pi. 85, fig. 64-67. G. W. Tryon, Phila- delphia. [Brief account of extinct forms.] Turek, V. and R. J. Prokop. 1982. Two remarkable finds of molluscs in the Carboniferous of Slovakia. Casopis pro Mineralogii a Geologii 27(3):285-293, pi. 2, text-fig. 2. [De- scribes Rhombichiton ochtinensis.] Van Belle, R. A. 1975a. Sur la classification des Polypla- cophora: I. Introduction et classification des Paleoloricata, avec la description de Kindbladochiton nom. nov. (pour Eochiton Smith, 1 964). Informations de la Societe Beige de Malacologie, ser. 4, no. 5, pp. 121-131, pi. 1, fig. 1-11. . 1975/?. Sur la classification des Polyplacophora: II. Classification systematique des Lepidopleurina (Neolorica- ta), avec la description des Helminthochitoninae nov. subfam. (Lepidopleuridae) et de Mesochiton nov. gen. (Helmintho- chitoninae). Informations de la Societe Beige de Malacologie, ser. 4, no. 6, pp. 135-145, pi. 2-3. . 1978. Sur la classification des Polyplacophora: VII. Errata, additions et rectifications. Resume de la classifica- tion. Index alphabetique. Informations de la Societe Beige de Malacologie, ser. 6, no. 3, pp. 65-82. Walcott, C. D. 1885. Note on some Paleozoic pteropods. Amer. J. Sci. 30:17, pi. 20, fig. 1-6. . 1886. Studies on the Cambrian faunas of North America. U.S. Geol. Surv. Bull. 30:223-225, pi. 32, fig. 1-12, pi. 33, fig. 1, la-f. [Describes Matthevia variabilis.] . 1912. New York Potsdam-Hoyt fauna, in Cambrian geology and paleontology. Smithson. Misc. Coll. 57(9):25 1- 304, pi. 37-49. Wanless, H. R. 1958. Pennsylvanian faunas of the Beards- town, Glasford, Havana, and Vermont quadrangles. 111. Geol. Surv., Rept. Invest. 205, pp. 21, 39. [Lists Glaphurochiton carbonarius (Stevens).] Weller, S. 1903. The Paleozoic faunas. New Jersey Geol. Surv., Paleontology 3:173-174, pi. 13, fig. 1-10. [Describes an unnamed polyplacophoran plate from the Trenton Lime- stone.] Whidborne, G. F. 1892. A monograph of the Devonian fauna of the south of England. Palaeontogr. Soc. 2(4):333- 335, pi. 31, fig. 15a, b, 16. [Describes Helminthochiton papi- lio.] Whitfield, R. P. 1882. On the fauna of the lower Carbon- iferous limestones of Spergen Hill, Ind., with a revision of the descriptions of its fossils hitherto published, and illus- trations of the species from the original type series. Bull. Amer. Mus. Nat. Hist. 1(5):96. [Lists Chiton carbonarius Stevens.] Williams, J. S. 1943. Stratigraphy and fauna of the Louisiana Limestone of Missouri. U.S. Geol. Surv. PP 203:100-101, pi. 9, fig. 19-20. [Describes Gryphochiton? anomalus (Row- ley).] Wilson, A. E. 1951. Gastropoda and Conularia of the Ottawa Formation of the Ottawa-St. Lawrence lowland. Geol. Surv. Canada, Bull. 1 7, p. 1 6, pi. 1 , fig. 1-3. [Describes Priscochiton canadensis Billings.] Withers, T. H. 1926. Catalogue of the Machaeridia ( Tur- rilepas and its allies) in the Department of Geology British Museum (N.H.), pp. 34-42, pi. 5, fig. 1-6, pi. 6, fig. 1-8. [Discusses "Chiton" wrightianus de Koninck, a barnacle.] Wood, W. 1815. General conchology: or, a description of shells, arranged according to the Linnean system and illus- trated with plates, drawn and coloured from nature, Vol. 1. John Booth, London. 246 pp. Woodward, H. 1865. On the discovery of a new genus of Cirripedia in the Wenlock limestone and shale of Dudley. Quart. J. Geol. Soc. London 21(4):486-489, pi. 14, fig. la- 1. [Good discussion of Chiton wrightianus, C. loftusianus, and C. grayanus with respect to their validity as polypla- cophorans.] . 1885. On a new species of Helminthochiton from the Upper Bala (Silurian) of Girvan, Ayrshire. Geol. Mag., de- cade III, 2:352-355, pi. 9, fig. 7-11. [Describes Helmintho- chiton grayiae.] Yochelson, E. L. 1966. Mattheva, a proposed new class of mollusks. U.S. Geol. Surv. PP 523-B:Bl-B9, pi. 1. . 1971. The Permian nautiloid mandible Rhynchoteu- this kaibabensis reinterpreted as a polyplacophoran. J. Pa- leontol. 45( 1 ): 1 30-1 33, 1 fig. [Describes Cymatochitonl kai- babensis (Brady).] Yochelson, E. L., J. F. McAllister, and A. Reso. 1965. Stratigraphic distribution of the Late Cambrian mollusk Matthevia Walcott, 1885. In Geological Survey Research, 1965, U.S. Geol. Surv. PP 525-B:B33-B78, fig. 1-5. [Gives localities where Matthevia occurs in California, Nevada, Texas, and Utah.] Yochelson, E. L. and E. S. Richardson, Jr. 1979. Pol> placophoran molluscs of the Essex fauna (Middle Pennsyl- vanian, Illinois). Pp. 321-332, fig. 1-5 in Mazon Creek Fos- sils, H. Nitecki, ed. Academic Press, New York. [Discusses Pterochiton concinnus (Richardson).] Yochelson, E. L. and B. W. Saunders. 1967. A biblio- graphic index of North American Late Paleozoic Hyolitha, Amphineura, Scaphopoda, and Gastropoda. U.S. Geol. Surv., Bull. 1210:11-13. Yochelson, E. L. and M. E. Taylor. 1974. Late Cambrian Matthevia (Mollusca, Matthevida) in North America. Geol. Soc. Amer. Abstr. for 1974, Northeastern Section, p. 88. MBL/WHOI llBRARy UH 116b SMITH AND HOARE: PALEOZOIC POLYPLACOPHORA 71 Young, J. 1865. Provisional notice of a new Chiton, and a new species of Chitonellus, from the Carboniferous rocks of western Scotland; with descriptions by Mr. James W. Kirk- by. Trans. Geol. Soc. Glasgow 2(1): 13-1 5, pi. 1, fig. 1-2. [Describes Chiton humilis Kirkby and Chitonellus youngi- anus Kirkby.] . 1878. On Chitonellus, recent and fossil. Proc. Nat. Hist. Soc. Glasgow 3:322-324. [A general account adding no new information; not of taxonomic significance.] Young, J. and J. Young. 1868. In On new forms of Crus- tacea from the Silurian rocks at Girvan, J. Young. Proc. Nat. Hist. Soc. Glasgow 1:169-173, pi. 1, fig. 7a-b. [Describes Solenocaris solenoides.] Yi), Wen. 1984. Early Cambrian molluscan faunas of Mei- schucun Stage with special reference to Precambrian- Cambrian boundary. A Special Paper on the "Academia Sinica Developments in Geoscience, Contrib. to 27th In- ternat. Geol. Cong., Moscow," pp. 21-35, pi. 1, fig. 1-9. [Describes Yangtzechiton elongatus n. gen., n. sp. and Luy- anhaochiton spinus n. gen., n. sp.] Zittel, K. A. von. 1885. Handbuch der Palaeontologie, Abth. 1, Bd. 2, Placophora, pp. 172-174, fig. 209. R. Oldenbourg, Munich and Leipzig. [Brief mention of fossil occurrences.] . 1924. Grundziige der Palaontologie (Palaozoologie). Neubearbeitet von Dr. Ferdinand Broili, O. Professor an der Universitat Munchen. Chitons (Amphineura), pp. 435-437, fig. 802-803. R. Oldenbourg, Munich and Berlin. [Brief gen- eral account. Illustrates Chiton (Gryphochiton) priscus Miinster and Lepidopleurus virgifer Sandberger.] % ■■ .?*•**. ■■. '£<*>;